More American celebrities are speaking out as the protests that have swept the US in the wake of George Floyd's death show no signs of receding.
Mr Floyd, who was African-American, died in Minneapolis last week while in police custody, with a bystander's video showing a white officer putting his knee on his neck for several minutes.
His death sparked a wave of anger, with demonstrations continuing across major US cities.
Many cities, including Los Angeles and New York, are under curfew orders in an attempt to quell the protests.
In an address from the White House Rose Garden on Monday, Donald Trump threatened to deploy the military if state governors did not halt the violence.
The president then walked to the nearby St John's Church and posed for pictures while holding a bible.
Singer John Legend, a frequent critic of the president, accused Mr Trump of using law enforcement to clear peaceful protesters so he could get a photograph.
He tweeted: "#BunkerBoy Trump had to prove he could walk in broad daylight today so he sicced the police on peaceful protesters so he could stand there and awkwardly hold the Bible. Dear God. We need to end this nightmare of a presidency."
#BunkerBoy Trump had to prove he could walk in broad daylight today so he sicced the police on peaceful protesters so he could stand there and awkwardly hold the Bible. Dear God. We need to end this nightmare of a presidency. https://t.co/umEY90OTcy— John Legend (@johnlegend) June 2, 2020
Oscar-winning filmmaker Spike Lee, who refers to Mr Trump as "Agent Orange," wrote on Instagram that the US was on the verge of a dictatorship.
Grammy-winning rapper Cardi B accused the president of threatening people and making protesters "more angry".
Samuel L Jackson suggested Mr Trump had "declared war on the public," admitting he fears "it's about (to) get all kinds of f***ed up here!!".
Following Mr Trump's press conference, One Direction star Niall Horan, who earlier accused the president of "hiding", wrote: "Can't believe what I just watched."
Can't believe what I just watched.— Niall Horan (@NiallOfficial) June 1, 2020
Earlier, George Clooney penned an essay for The Daily Beast, saying America's greatest pandemic is racism.
He wrote: "How many times have we seen people of colour killed by police? Tamir Rice, Philando Castile, Laquan McDonald. There is little doubt that George Floyd was murdered.
"We watched as he took his last breath at the hands of four police officers. Now we see another defiant reaction to the systemic cruel treatment of a portion of our citizens like we saw in 1968, 1992, and 2014."
The Hollywood star also criticised Mr Trump for his controversial comments amid the protests, with one of his tweets reading: "When the looting starts, the shooting starts."
Clooney added: "We need policymakers and politicians that reflect basic fairness to all of their citizens equally. Not leaders that stoke hatred and violence as if the idea of shooting looters could ever be anything less than a racial dog whistle."
Chart-topping star Adele also lent her support to the Black Lives Matter movement, warning against the campaign becoming "disheartened, hijacked or manipulated right now".
She wrote: "This is about systematic racism, this is about police violence and it's about inequality. And this isn't only about America! Racism is alive and well everywhere.
"I wholeheartedly stand in solidarity with the fight for freedom, liberation and justice."