Ellison warns: “In order to be thorough, this is going to take months. It is better to make sure that we have a solid case, fully investigated, researched, before we go to trial, than to rush it. It will take a while, I can’t set a deadline on that.”

Ellison acknowledges that the prosecution of officers in the George Floyd case alone will not rectify larger injustices experienced in American society.

"We need citizens, neighbours, leaders in government and in faith communities, civil and human rights activists to begin rewriting the rules for a just society now," he said.

"We need new policy and legislation and ways of thinking at the municipal, state and federal levels."

He adds that the entertainment and arts industry could also use "cultural influence to inspire change".

"There is a role for all who dream of a justice that we haven't yet experienced."

Minnesota Attorney General Keith Ellison says that while "speed is important", his team are "investigating as thoroughly as we can".

"The reason thoroughness is important is because every single link in the prosecutorial chain must be strong. Winning a conviction will be hard." He stresses that there have not been many successful convictions of police officers in the state.

George Floyd's life had value, he says, and "we will seek justice for him, and for you. The very fact we have filed these charges [shows] we believe in it."

Only one current prosecutor has won a successful conviction against a police officer in Minnesota, he notes.

Minnesota Attorney General Keith Ellison starts with what he calls "a reminder".

"We are here today because George Floyd is not here. He should be here, he should be alive, but he is not," he said.

He says his team has "reviewed the evidence" and has today "filed an amended complaint that charges former Minnesota police officer Chauvin with murder of second degree. I believe the evidence available now supports the stronger charge."

Arrest warrants have also been issued for the three other police officers, Tou Thao, Thomas Lane and J Alexander Kueng, who will face charges, he added.

Minnesota Attorney General Keith Ellison is expected to give a press conference shortly detailing the new charges in the George Floyd case. We'll bring you details from the press conference as it happens.

Image source, Reuters

Court documents show that the three former US police officers seen watching as Derek Chauvin knelt on George Floyd's neck will now also face charges.

Tou Thao, Thomas Lane and J Alexander Kueng face counts of aiding and abetting murder, the documents state.

Meanwhile, Chauvin has been charged with second-degree murder in addition to the initial third-degree murder charge. Second-degree murder carries a maximum prison sentence of 40 years.

BBC OS

As protests raged earlier this week in Louisville, Kentucky, a woman was filmed hugging an armed police officer.

The emotional exchange was captured by Vice News reporter Roberto Ferdman and has been shared thousands of times on Twitter.

The woman in the video, Tonya Trumbo, is a teacher and told the BBC she was there to support several of her students as they took part in demonstrations.

"Even though I was trying to be the role model and be in control, my emotions spilled over," said Tonya.

As she found herself chastising police officers nearby, one beckoned her over.

"He just whispered 'Are you OK?' and my emotions spilled right over into his arms," she said. "I was able to feel safe for just a moment. I was just happy the kids were able to see that."

Despite the hug, Tonya said, tearfully, that she was "not OK."

"Even after that happened, here in Louisville, Kentucky, I got up [the next] morning and we had somebody else who was shot by a police officer in our neighbourhood".

"We don't even have a relationship with the police officers anymore," she added. "It's gone from protecting and serving to just policing."

Snapchat says it has stopped promoting President Trump's account on its Discovery section, vowing to "not amplify voices who incite racial violence and injustice".

The decision follows Mr Trump saying that "vicious dogs" and "ominous weapons" would have been used on protesters if they had breached the White House fence.

In a statement, Snapchat said: "Racial violence and injustice have no place in our society and we stand together with all who seek peace, love, equality, and justice in America."

The move is likely to feed into tensions between the White House and social media companies, which escalated when Twitter added fact-checking tags to some of the President's tweets last week.

In response, he called for legislation to curb legal protections offered to the industry.

Read more:

Snapchat stops promoting Trump's account due to 'racial violence'

A lawyer representing George Floyd's family has welcomed the expected decision by the Minnesota attorney general to upgrade murder charges against the officer who kneeled on Floyd's neck, and bring charges against the three other officers involved in Floyd's arrest and death.

However, he stressed that this was "a bittersweet" moment for the family.

Ex-officer Derek Chauvin is currently charged with third-degree murder, which applies to any person who “causes the death of another by perpetrating an act eminently dangerous to others and evincing a depraved mind, external, without regard for human life.”

Prosecutors are expected to upgrade the charges against him to second-degree murder later today.

Under Minnesota law, for charges of first- or second-degree murder, prosecutors typically need to prove there was a deliberate intent to kill.

Typically, first-degree murder charges are "premeditated" or planned in advance, while second-degree charges are applied to crimes of passion.

Lots of questions were raised in today's White House briefing about Defence Secretary Mark Esper.

Earlier today, Esper said that he disagreed with the idea of sending active-duty troops into cities to quell protests, and said he did not know his visit to a church opposite the White House on Monday would be a "photo-op".

White House spokeswoman Kayleigh McEnany spent little time defending the the Pentagon chief.

When asked about reports that Trump was angered by Esper's comment's earlier today, she replied: "If he loses confidence in Secretary Esper I’m sure you all will be the first to know."

"As of right now Secretary Esper is still Secretary Esper and should the president lose faith we’ll all learn about that in the future."

Defence Secretary Mark Esper said today that he does not support invoking the Insurrection Act, a 19th Century law that allows the federal government to send the military into states.

White House Press Secretary Kayleigh McEnany says Trump may still enact the Insurrection Act "if needed".

She calls the act "a tool available to the president who has the sole authority" to use it.

So far, the National Guard has been ordered into states and cities at the request of governors and mayors, not the president.

The only place where active-duty US troops have been deployed is to Washington DC.

Can Trump send in the army?

Mr Trump has come in for criticism after police dispersed mostly peaceful protesters on Monday, to clear a way for him to stand outside the nearby St John's Church clutching a Bible.

"Officers had no other choice but to take that action for their safety," McEnany says, defending the decision to expand the security around the perimeter.

The decision was made "so that church would no longer be in harm's way by those protesters," she said. The St Johns church suffered a fire on Sunday night, but did not see significant damage.

She also accused protesters of throwing bricks and frozen water bottles at police. Reports from the ground said that the vast majority of protesters were peaceful.

The presiding bishop of the the Episcopal Church, Michael Curry, has accused Mr Trump of using the church for "partisan political purposes", while the Archbishop of Washington Wilton D Gregory said that the president had "manipulated" the church.

Image source, White House

White House spokeswoman Kayleigh McEnany is speaking now, in the first briefing since Trump walked through a dispersed protest to visit a church.

"The First Amendment doesn’t give anyone the right to riot," she says, adding nor does it give anyone the right to "loot", "burn down buildings", or "assault private citizens and assault police officers".

Protesters opposite the White House on Monday were demonstrating peacefully before they were removed for Trump and his aides to visit a nearby church.

McEnany also invoked civil rights icon Dr Martin Luther King and the 1963 March on Washington where he spoke from the Lincoln Memorial.

Minnesota Attorney General Keith Ellison is expected to speak in the coming hours about the death of unarmed black resident George Floyd, whose death last week triggered protests across the US.

Minneapolis policeman Derek Chauvin, who had his knee pressed on Floyd's neck, has already been charged with third-degree murder and second-degree manslaughter.

Ellison is expected to upgrade the charge against him to second-degree murder, and charge the other three arresting officers, according to news reports.

Ex-officers Thomas Lane and J.A. Keung, who assisted in restraining Floyd, and Tou Thao, who stood near the others, have all been fired from the police force, but this would be the first criminal charges they face.

They are expected to be charged with aiding and abetting murder, the Minneapolis Star-Tribune reports.

The decision, which has yet to be formally announced, has been praised by Minnesota Senator Amy Klobuchar as "another important step for justice".

Anthony Zurcher
BBC North America reporter

The prospect of US active duty military forces operating on US soil to secure US cities – whether local officials wanted them there or not – has become too much to stomach for a growing number of current and former military officials.

“America is not a battleground. Our fellow citizens are not the enemy,” Martin Dempsey, a former general and chairman of the Joint Chiefs of Staff, tweeted on Monday after Donald Trump suggested such a rare move.

Defence Secretary Mark Esper, who in a Monday White House conference call had described US cities as “battle space", has felt the heat in particular. On Tuesday, one of his policy advisers resigned in protest. Esper noted that he did not know that Lafayette Square, across from the White House, had been forcibly cleared of protestors by law enforcement – including National Guard soldiers - so the president could visit a nearby church.

Now he’s trying to downplay the likelihood of further military action.

That Esper is risking a break with Trump – and drawing the kind of presidential ire that does not easily dissipate – suggests he may feel that calming the nerves of the military leadership is a higher priority.

This would not be the first time the president has announced a drastic and confrontational action that is never fully implemented by his military advisers. Such a situation led to an irreparable rift between Trump and his first defence secretary, James Mattis.

After one night of relative calm, however, a military deployment appears less necessary even to its advocates, while the downsides of crossing US governors and putting US armed forces in an unwanted and unfamiliar situation have become increasingly obvious.

Rather than feuding with Esper, Trump might want to claim success and move on.

Prime Minister Boris Johnson has said is appalled and sickened by the death of George Floyd, and that his message to people in the US is that "racist violence has no place in our society".

Speaking at the government's daily coronavirus briefing, he said that people in the UK “have the right to protest”, but urged demonstrators to “protest peacefully and in accordance with rules of social distancing".

Monuments to leaders who fought against the federal United States government during the Civil War (1861 to 1865) are being dismantled throughout the country, as they become targets of protesters.

Memorials to the Confederacy, which fought for the legal right to keep black people as slaves, have been vandalised and defaced for years, and have been criticised as an everyday symbol of institutionalised white supremacy.

In Birmingham - Alabama's largest city - the mayor pleaded with residents to hold off on toppling a five-storey tall monument, after they had already taken down a statue of a general in the same park. He asked that they wait, so he could order for it to be removed, which he did.

The state's attorney general is now suing, saying the move violates the Alabama Memorial Preservation Act, which was passed in 2017 to "protect architecturally significant buildings, memorial buildings, memorial streets, and monuments located on public property for 40 or more years".

Most Confederate statues in the US were erected during the Jim Crow and Civil Rights eras, rather than in the direct aftermath of the Civil War.

Alexandria, Virginia, opposite the Potomac River from Washington DC, has also seen the removal of a Confederate General.

The mayor of the city tweeted his approval.

How America moves beyond its racist past

Image source, Getty Images

Former US President Barack Obama is expected to join a panel of speakers discussing police violence and racism within law enforcement.

The talk will be broadcasted on his website, external live from 1700 ET (2200 BST) today, as part of a series of talks hosted by the Obama Foundation.

Joining him will be former Attorney General Eric Holder, plus activists and politicians who are calling for police reform.

Obama has previously given a statement on George Floyd's death and the subsequent protests, but these will be his first on-air remarks.

Image source, Reuters

George Floyd's son, Quincy Mason Floyd, is speaking at the scene of his father's death in Minneapolis.

He tells repoters and protesters that he's out there “trying to get justice for my father".

"No man or woman should be without their fathers... And we want justice for what is going on right now.”

He's asked about global protests in support of his father that are happening as far away as Australia.

"I appreciate everyone showing support and love and I thank you all for that," he says."I just want to thank them for supporting my family."

Image source, Reuters