A shocked performer has described locking eyes with US President Donald Trump as they ducked for cover after shots were fired at the White House Correspondents' Association dinner on Saturday night in Washington DC.

Oz Pearlman - a self-described "mentalist" performing mind tricks - told the BBC he was talking to Trump, First Lady Melania Trump and White House press secretary Karoline Leavitt when the attack happened.

"I went down very quickly. And then the Secret Service brought President Trump down: I would say very effectively - but quite violently," he said.

"We were about half-a-metre apart… face-to-face looking at each other on the ground, when I'm hearing shots and thinking to myself, 'We're about to die.'"

Footage from the annual event showed Pearlman standing with a piece of paper behind the three VIPs, who were all seated at a table on an elevated stage at the Washington Hilton hotel.

"The timing of it was just so crazy because I was right in the midst of performing for the first lady, and for the president and for the press secretary… guessing the name – the press secretary is having a baby soon," Pearlman said.

He said he was trying to guess how many letters were in the baby's name, and as he ripped off a piece of paper and showed the name, he heard the gunshots.

At the time, he thought "there was about to be a bomb because of the way they [secret service agents] were all going towards one table.

"It didn't feel like they were looking for a shooter. It felt like they were looking to stop something from happening."

Pearlman said he then "went down very quickly".

"I was facing stage left. And just by chance they [agents] tackled him [Trump], right next to me facing stage right.

"And I'm turned to the left looking directly into his eyes - for 'One Mississippi, Two Mississippi' - pretty much thinking that I hope I'm not about to die."

Pearlman said about "two seconds later" the agents got Trump out of the room, while he himself and two other people nearby eventually "crawled out" to safety.

In an interview with CBS's 60 Minutes on Sunday, Trump said he "wasn't worried" during the ordeal. "I understand life. We live in a crazy world."

Asked about his recollection of "going down" as he was led from the room by security agents, he recalled how he "started walking with them [the security team]. I turned, I started walking, and they said, 'Please go down. Please go down on the floor.'

"So I went down and the first lady went down also."

A suspected gunman was arrested at the venue following the firing of gunshots, and was named by law enforcement officials as Cole Tomas Allen.

Police said the 31-year-old exchanged fire with security agents on the floor above the room where Trump had gathered with other attendees for the event.

After he was detained, Allen told officials he wanted to shoot officials in the Trump administration, two sources told CBS, the BBC's US news partner.

Allen, from California, will be formally charged at a hearing in Washington later on Monday.