Only hours after arriving back in Washington from a diplomatic tour of Africa, US Secretary of State Rex Tillerson learned through a presidential tweet that he was being replaced.

CIA Director Mike Pompeo - a former ultra-conservative congressman - has been nominated by the president to replace the top US diplomat.

Pompeo's deputy at the CIA, Gina Haspel, has been named to become the next American spymaster.

Both Pompeo and Haspel must be confirmed by the Senate before they can take up their new roles.

If confirmed, Haspel - who ran US "black sites" where terror suspects were tortured - will become the first female director of the agency.

As for Tillerson, he told reporters he plans to "return to private life as a private citizen", and will presumably enjoy a comfortable retirement with his pension from ExxonMobil, where he was formerly CEO.

For more read our main news story here:

Trump fires Rex Tillerson as secretary of state

The Council on American-Islamic Relations, the largest Muslim lobbying organisation in the US, has released a statement opposing the nominations of Pompeo and Haspel.

"Those, like Mr Pompeo, who have expressed Islamophobic views and have been associated with an anti-Muslim hate group, or like Ms Haspel, who personally oversaw the torture of detainees, should have no role in our nation's government, let alone at the highest levels of policy-making," the group's director said in a statement.

Image source, EPA

Senator Chuck Schumer, the highest-ranking Democrat in the Senate, says Tillerson was "not close to tough enough" on Russia, a country that had previously given the sacked secretary of state an honour called the Russian Order of Friendship.

Schumer added that he has not called on his Democratic colleauges to oppose the nominations of Pompeo and Haspel.

He says he wants to hear from them first before deciding whether to try to block their appointments.

"On Tillerson: hallelujah!" one Department of State employee told the Daily Beast.

"Tillerson kept a lot of the crazy in check and was obviously a moderating voice. But he never had the ear of" the president, another official at the department adds.

Foggy Bottom employees are said to be both grateful for and fearful about the Washington shake-up.

Tillerson had made it a priority to slash funding for state department programmes, as well as staff numbers, making many enemies inside the agency.

Mike Pompeo has a better relationship with the US president, but is considered one of Washington's most hawkish figures.

"Pompeo will have the president’s trust but enable his worst foreign policy instincts," a current diplomat tells the news website, external.

"Sanity has never been the guiding principle of this White House."

The sudden ousting of US Secretary of State Rex Tillerson ignited Twitter, the president's chosen medium for delivering the news.

Given that Trump became a household name hosting US television show The Apprentice, some joked about his apparent reluctance to deploy in person the programme's famous catchphrase: "You're fired!"

Others drew comparisons to Mr Comey's departure.

For more social reaction, check out our story here.

Under Secretary of State for Public Diplomacy and Public Affairs Steve Goldstein, who was fired today for contradicting the White House account of how Tillerson was fired, spoke to the BBC last week.

He dismissed reports that Tillerson was on shaky ground, calling him the "Secretary of Stay".

While Tillerson just lavished fulsome praise on the department he led, the admiration was apparently not mutual.

State Department staff are reportedly experiencing a "strong sense of relief" that he is out.

"The last year has been traumatic to put it mildly. It was as though 'T-Rex' stomped through Foggy Bottom devouring staff and structures," Brett Bruen, a former State Department official, told Politico.

Since coming into office, Trump has largely sidelined the diplomatic agency, choosing to conduct international affairs from the White House.

“People see this as a chance for a clean sweep,” said another employee, who wished to remain anonymous.

According to the newspaper, external, Department of State staff view Pompeo as personally closer to Trump and more likely to help them gain influence.

Image source, Reuters

"I now return to private life, as a private citizen, as a proud American," says Tillerson, who read from his statement the entire time.

He did not take any questions, and walked off stage quickly.

Several commentators suggested he appeared to be out of breath as he made his dignified remarks, which did not refer to the abrupt manner of his sacking.

He says Washington must do more to respond to Russia's "troubling behaviour and actions".

"Russia must assess carefully how its actions are in the best interest of the Russian people and the world more broadly."

"Continuing on their current trajectory is likely to lead to greater isolation," says Tillerson.

Tillerson is outlining his diplomatic achievements during his tenure and remaining in-tray items, from Syria to the Islamic State group.

"US leadership starts with diplomacy," he says.

"The rewarding part of having leadership and partnerships in place is you can actually get some things done," he says before going on to praise US allies.

Addressing his fellow government workers, Tillerson says: "We all took the same oath of office.

"We are all bound by the common commitment, to support and defend the constitution.

"We remain steadfast here in Washington and at posts across the world.

"The world needs selfless leaders like these."

Tillerson says he received a call from the president on Air Force One a little after noon, about three hours after Mr Trump announced his firing via tweet.

"What is most important is to ensure an orderly and smooth transition during a time that the country continues to face significant policy and national security challenges," Tillerson says.

He adds that he is stepping down on 31 March and delegating all his responsibilities to his deputy.

Jon Sopel
BBC North America Editor

The end was a perfect metaphor for the relationship. The odd couple of politics had been yoked together for too long.

Men of different temperaments, demeanour and style had reached a parting of the ways.

The secretary of state landed back at Joint Base Andrews to have a member of staff inform him that the president had tweeted.

Because Mr Tillerson is not on Twitter, the tweet had to be printed out. Fancy being the one tasked with handing that over to the boss. Fired by a tweet.

The career of a one-time giant of corporate America had come to an ignominious end.

Read Jon Sopel's full blog post here:

Tillerson sacking: Where it went wrong for Rex

Sacked Secretary of State Rex Tillerson will hold a press briefing from the State Department at 14:00 local time (18:00 GMT). Stay tuned for live updates.

Barbara Plett Usher
State Department correspondent, BBC News

Rex Tillerson had a difficult tenure defined by his rocky relationship with President Trump.

Rumours of his ouster swirled late last year.

They had died down in recent months, until, with shocking abruptness, Trump fired his top diplomat via Twitter, just hours after he got back from a trip to Africa.

Senior state department officials said Tillerson had been warned something was coming, but he only learned what exactly it was when he read the tweet.

Things didn’t go very well for Rex Tillerson. As the head of Exxon he came into the job with a lot of foreign negotiating experience, but none in government, and none with diplomacy.

Under his watch there was an exodus of veteran diplomats and expertise.

He did better on the diplomacy side, taking an establishment Republican line in crafting policies and ready to counsel against Mr Trump’s instincts on issues such as Iran and North Korea.

But the two men have very different personalities, and the tension in their relationship was not diffused after Tillerson reportedly called the president a "moron".

That was a very low point, but Tillerson had worked on the relationship since then, and it seemed to be improving.

In the end Trump chose to replace him with Mike Pompeo, with whom the president has a personal chemistry.

Pompeo is a hawk on Iran and has spoken belligerently about North Korea.

He will work closely now with Trump on the fate of the Iran deal, and the forthcoming historic summit with the North Korean leader Kim Jong-un.

According to state department journalists, Under Secretary Steve Goldstein - who told reporters this morning that Tillerson was unaware he was being fired until he was alerted by Trump's tweet - has now been fired by the White House.

Image source, Getty Images

Democratic Senator Ben Cardin said in a statement that "Tillerson’s firing is symptomatic of President Trump’s inability to take independent advice from his advisers".

The Maryland senator adds that he voted against Pompeo as CIA director because of his view that Guantanamo Bay should stay open, but he is now "hopeful that after his time at the CIA, Director Pompeo has a greater appreciation for the balance between national security and civil rights".

Senator Chris Coons - also a Democrat on the Senate Foreign Relations Committee - said he does not "believe that President Trump ever gave [Tillerson] the trust, personnel and resources he needed to be effective as the nation’s top diplomat".

"Tillerson's firing comes one day after he once again spoke out against Russia when the President would not," Coons adds referring to the poisoned Russian former spy who is in a coma after suffering a biological attack in southern England.

California Senator Dianne Feinstein said Tillerson was dismissed simply for having a "different point of view" than the president.

Image source, EPA

"We are grateful for the excellent relationship and co-operation that we have had with Rex Tillerson and look forward to that continuing under the new US Secretary of State," says a spokesman for British Prime Minister Theresa May.