President Donald Trump and members of his family are attending a multi-faith prayer service at Washington National Cathedral.

Among the other attendees are Trump's daughters, Ivanka and Tiffany Trump and their husbands, and Trump's son, Eric Trump.

Image source, Reuters

Image source, AFP

Image source, AFP

The BBC has been out and about in DC speaking to Trump's supporters and asking them what their message is for liberal America.

How will other countries respond to US policy changes?published at 16:36 Greenwich Mean Time 21 January

16:36 GMT 21 January

James Landale
Diplomatic correspondent

They are all bracing themselves for this flood of polices, some of which will affect them in this first 24 hours, maybe their turn is in the next few days.

Essentially what they're learning is that Donald Trump in the past started slowly and built up, this time he has learned, he knows what he wants to do and he is going at a full pace.

I think what they've realised now is that it's not just a question of flattering him or saying nice things about him, but that if you wish to persuade Trump of your position you have to appeal to his self-interest.

We've just heard from President Zelensky of Ukraine today making a speech that was entirely aimed at Donald Trump even though it was given to a European audience. In other words, saying to the Europeans you have got to do more on defence because that it what the Americans want.

That's a wrap on the Q&A session with our correspondents. We'll continue to look at Trump's orders and their potential impacts, so stay with us.

Dominic Hughes
Health correspondent

"Damaging", "disastrous", "catastrophic" – this is how some global public health experts are describing the decision to withdraw the United States from the WHO.

The most obvious impact will be on the funding of the global health body.

Of the 196 member states, the US is by far the largest individual funder, contributing almost a fifth of the total WHO budget. It's possible that funding could disappear almost overnight and it is not at all clear that other nations will step up to fill the gap.

That could have an impact on the ability of the WHO to respond to emergencies such as an Ebola outbreak, or mPox – let alone another Covid-19-style pandemic.

There is also concern among some scientists that withdrawing from the WHO could leave the US isolated when it comes to access to programs such as pandemic preparedness and seasonal influenza strain sequencing, which is used to develop annual flu jabs.

That could ultimately harm the health of Americans, and the US national interest.

What retaliation is likely from Mexico and Canada over tariffs?published at 16:30 Greenwich Mean Time 21 January

16:30 GMT 21 January

Dharshini David
Chief economics correspondent

In the past, we've seen other countries retaliating by hitting America where it hurts. They can respond with tariffs of their own, on specific goods designed to have maximum political impact.

So, we'll have to wait and see, but it could result in a tit-for-tat trade war where consumers tend to lose out.

We don't know when the tariffs will come into force. Or how much he will enact on it in practice - perhaps it's a threat to the rest of the world.

But other countries selling into America, could benefit.

It could create big opportunities for the likes of countries, such as Vietnam and Malaysia, to increase their production for a US market.

Bernd Debusmann Jr
Reporting from the White House

A little earlier, we looked at whether Trump's immigration plan will work.

Broadly speaking, polls show that a majority of Americans support the concept of mass deportations of undocumented immigrants living in the US.

A recent Ipsos poll released just this Sunday, for example, suggested that 66% of Americans favour mass deportations.

This is true of a vast majority - 93% - of Republicans, as well as 43% of Democrats.

The same poll, however, suggested that support slips when specific policies are included. Only about 34% of people, for example, support deporting immigrants who were brought to the US illegally as children.

On a recent reporting trip to heavily Latino south Texas - where many people are immigrants themselves, or the children or grandchildren of immigrants - many people said they supported the deportations and told me that migrants should come the "right way".

Trump and officials in his administration have suggested that deportations would begin with criminals or those already with deportation orders - a strategy that has found a receptive audience among many in south Texas.

When will the US withdraw from the Paris climate agreement?published at 16:26 Greenwich Mean Time 21 January

16:26 GMT 21 January

Matt McGrath
Environment correspondent

A sense of deja vu. Back in 2017 Donald Trump first set out to take the United States out of the Paris climate agreement.

He had to serve a three-year cooling off period then, so he was only able to leave the agreement right at the end of his presidency. He doesn't have to suffer that this time – he will be able to leave in 12 months' time from giving the notice yesterday.

The reaction around the world has been pretty muted in many ways because this had been expected.

We've had some reaction from China – a Chinese spokesman saying they were studying this and they were concerned about it, but that Beijing would continue the fight against climate change.

The UN said that their door is always open and if a future president wanted to come back into the agreement they would be most welcome.

How realistic is Trump's promise to end war in Ukraine?published at 16:22 Greenwich Mean Time 21 January

16:22 GMT 21 January

Frank Gardner
Security correspondent

Trump has famously said in the past the he would be able to end the conflict in the first 24 hours of his presidency. Obviously that's not going to happen. It's going to take months.

The problem is that whatever plan his designated chief general comes up with to resolve the conflict, there's no getting away from the fact that the two sides are still far apart in what they will accept.

Putin still hasn't given up aims of pulling Ukraine into Moscow's orbit. Ukraine hasn’t given up on hopes on guaranteeing its security.

There is also a serious risk for Ukraine that Trump is simply going to pull the plug on weapons supplies.

Image source, AFP

In the last few minutes, President Donald Trump and First Lady Melania Trump have arrived at Washington's National Cathedral for a multi-faith service.

Vice-President JD Vance and Second Lady Usha Vance are also attending, as is Speaker of the House, Mike Johnson.

Attendees will be welcomed to the service by Right Reverend Mariann Budde, who criticised Trump during the Black Lives Matter protests of 2020.

The service will also feature prayers from other faith leaders.

You'll be able to follow the latest from Trump's movements, in addition to our Q&A session at the top of this page, so click watch live for a front-row seat to his first day back in office.

Image source, AFP

Can Trump rename Gulf of Mexico as Gulf of America?published at 16:15 Greenwich Mean Time 21 January

16:15 GMT 21 January

By Jake Horton

President Trump can change the name of the Gulf on official US government documents.

This has happened on some documents already - including a weather update from Florida's Republican governor which refers to "an area of low pressure moving across the Gulf of America".

What are the roadblocks?

Trump can’t force other countries or companies to change the name. For example, it’s currently still labelled as the Gulf of Mexico on Google Maps.

What is the impact?

There’s no formal international agreement for the naming of maritime areas - although there is a body which seeks to resolve disputes if raised.

So Mexico could raise an official dispute, and US and Mexico allies could be caught up in a diplomatic spat between the two countries.

How will Donald Trump's immigration plan work?published at 16:12 Greenwich Mean Time 21 January

16:12 GMT 21 January

Caitriona Perry
Chief BBC News presenter, Washington DC

The biggest thing Trump did in relation to immigration was declaring a national emergency along the border. This has freed up funding.

Right across the political divide there’s agreement that not enough money is being directed towards some of these immigration measures. It's agreed that more judges, basic processing, and better security is needed.

It also allows US military to be deployed along the border to secure and police it.

Tens of thousands of people who had immigration appointments have already had their appointments cancelled.

Our experts and correspondents are answering your questions live on what to expect from Donald Trump's second term.

Chief BBC News presenter Caitríona Perry, security correspondent Frank Gardner and environment correspondent Matt McGrath are now live from Washington DC and London, with diplomatic correspondent James Landale and chief economics correspondent Dharshini David joining later.

They'll be looking at the flurry of executive orders Trump signed since taking office, on areas such as immigration, climate, government reform and the economy.

You can follow the session at the top of this page, just click the watch live button.

Image source, Getty Images

Alaska Senator Lisa Murkwoski has said she "strongly" disagrees with Trump's decision to sign an executive action renaming the state's Mount Denali to Mount McKinley.

Trump said the name change would be done in honour of America's 25th president, William McKinley, whose tariff policies Trump admires.

Reacting to the move, Murkowski said: "Our nation's tallest mountain, which has been called Denali for thousands of years, must continue to be known by the rightful name bestowed by Alaska's Koyukon Athabascans, who have stewarded the land since time immemorial."

For context: Former President Barack Obama changed the mountain's name from McKinley to Denali in 2015 to reflect what North America's highest peak was called by native tribes.

We've just heard from Winston Pingeon, a former police officer who was on duty during the Capitol riot on 6 January 2021.

Asked by our colleagues on the BBC World Service Newshour programme about his reaction to the pardoning of 1,500 people convicted or charged in connection with the riot, Pingeon says it's a "slap in the face" to police officers who "quite literally were assaulted that day".

"It’s really an unprecedented thing to know that these violent felons who were convicted by a jury of their peers for crimes that were largely broadcast for all the country and world to see are going to walk free and be returned to their neighbourhoods," he says.

Pingeon, who left the Capitol Police ten months after the riot, says that on the day of the storming he was punched in the face, knocked on the back, pepper sprayed, and nearly stabbed by a flag pole.

He describes the riot as "unprecedented" and says it's "important that those who assaulted law enforcement be held accountable for their actions", adding that "now they are not".

Bernd Debusmann Jr
Reporting from the White House

Image source, Getty Images

Nearly 24 hours after Donald Trump officially became President of the United States, we've still not heard about any planned news conferences from the new White House press secretary, Karoline Leavitt.

Here in the press area of the White House, it's clear that many reporters are itching for an opportunity to ask her questions, particularly about the Trump administration's plans to accomplish some of the goals it has already outlined.

The briefings provide an opportunity to ask the White House about future plans, to clarify things and to explain the president's thinking on any particular topic.

They can often be tense - something we saw with increasing frequency in the latter part of Joe Biden's administration, particularly when the White House was asked about the war in Gaza, or Biden's age and political future.

Earlier, Leavitt confirmed that "the American people won't he hearing from me today".

Instead, pool reporters will hear from Trump directly at his infrastructure announcement this afternoon.

Speaking to Fox, Leavitt said that Trump is the "most transparent president in history" - which some reporters have suggested means that we'll have more opportunity to press him directly for answers.

Rachel Flynn
Live reporter

Image source, Getty Images

Mexican people can be sure its government will "always defend Mexico's sovereignty and independence", its president Claudia Scheinbaum says.

Speaking about Trump's executive orders, the president says Mexico will always support its nationals who are in the United States.

She says the order Trump signed declaring a national emergency at the southern border is "practically the same" as an order he signed in his first term in 2019. "It isn't new," she adds. The 'Remain in Mexico' order is also a repetition from his first term in December 2018, Scheinbaum explains.

On the renaming of the Gulf of Mexico, which she introduces with a smile and a laugh, she says the order says the US can call it the "Gulf of America" but this won't change what Mexico and the rest of the world call it.

Jessica Murphy
BBC News, Toronto

Image source, Reuters

Canadian Prime Minister Justin Trudeau is responding to President Trump's renewed threat - issued last night - that he might impose 25% tariffs on Canada.

"Canadian energy powers American manufacturing, business, homes," Trudeau told reporters this morning.

The PM nodded towards Trump's promise in his inauguration address that America will enter a "golden age".

"That will require steel, aluminium, critical minerals, energy," Trudeau said. "Canada has all those resources."

It's not certain Trump will move ahead with imposing the tariffs on 1 February, as he suggested in the Oval Office on Monday night. The same day, he signed a presidential memo seeking a review of US trade relationships by his officials.

That review is due 1 April.

But Trudeau said if he does proceed: "Canada will respond - and everything is on the table."

Jessica Parker
BBC News Berlin correspondent

Germany's Chancellor Olaf Scholz, who is attending the World Economic Forum in Davos, has just responded to a question about Elon Musk's gesture last night, which has been compared to a Nazi salute; something that's banned in Germany.

"On the question of the dealing of Elon Musk I had a lot of things to comment in the past because he was discussing a lot about Europe. And just to repeat what I already said, we have the freedom of speech in Europe and in Germany. Everyone can say what he wants, even if he is a billionaire. And what we do not accept is if this is supporting extreme right positions," he said.

"And this is what I would like to repeat again."

As a reminder, Elon Musk caused outrage over a one-armed gesture he gave during a speech celebrating the inauguration of Donald Trump yesterday.

A few hours ago he responded on X, saying: "Frankly, they need better dirty tricks. The 'everyone is Hitler' attack is sooo tired."

Image source, Reuters

We can now bring you some lines from Florida Senator Marco Rubio, who has just been sworn in as the next US secretary of state.

Rubio says everything the new administration does will depend on the answer to three questions: "Does it make us stronger? Does it make us safer and does it make us more prosperous?"

"If not, we will not do it," he says.

He calls this a "transformational" moment and says the US is moving towards a "new era" that will make the world a safer place. He adds that Trump made it clear that the primary role of US foreign policy will be peace.

Florida Senator Marco Rubio has just been sworn in as the next US secretary of state. The Senate confirmed him late on Monday, making him the first member of Trump's cabinet to get congressional approval.

Rubio has years of experience serving on the Senate Foreign Relations Committee and speaking out about international conflicts during his Senate tenure.

He is now the nation's top US diplomat, overseeing more than 70,000 federal employees working for the US Department of State.

Rubio is considered a foreign policy "hawk" - meaning someone who takes hard-line positions, in this case towards Iran as well as China.

• Read more about where America's new secretary of state stands on key world issues here