The leaders of the US Senate Intelligence Committee have said they want to interview President Donald Trump's son, campaign chairman and everyone else who was at a meeting last year with a Russian lawyer at Trump Tower.

"Sure, sure," the committee's Republican chairman, Senator Richard Burr, told reporters when asked if he wanted the committee to call in the attendees.

Senator Mark Warner, the panel's Democratic vice chairman, also said the committee wanted to see everyone who had been at the meeting.

Earlier, the top Democrat on the Senate Judiciary Committee, US Senator Dianne Feinsteing, said that former FBI director Robert Mueller has said Donald Trump Jr and Paul Manafort, campaign manager from March to August, were free to speak to the committee.

Mr Mueller is investigating allegations by US intelligence agencies that Russia interfered to help Mr Trump win the presidency and possible collusion between Moscow and the Republican's campaign.

Russia denies meddling in the campaign, and Mr Trump says there was no collusion.

If Mr Trump Jr were to appear before the judiciary committee, he would be the highest member of the president's inner circle of relatives and White House aides to testify in Congress about the Russia allegations.

Several congressional panels have investigations open.

The allegations have dominated Mr Trump's first six months in office.

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Mr Trump Jr, who runs the Trump Organization family business, released emails last week in which he eagerly agreed in June 2016 to meet a woman he was told was a Russian government lawyer who might have damaging information about Democratic election rival Hillary Clinton as part of Moscow's official support for his father's campaign.

The meeting in Trump Tower in New York appears to be the most tangible evidence of a connection between Trump's campaign and Russia, investigators in congress have said.

Judiciary Committee Chairman Charles Grassley has said he would coordinate with Mr Mueller to ensure that any witnesses the panel brings would not conflict with Mr Mueller's criminal investigation.

Ms Feinstein, asked whether Mr Mueller had given the go ahead for Mr Trump Jr and Mr Manafort to testify publicly, said, "yes."

She said the committee planned for the testimony to be part of a broader hearing scheduled for tomorrow but has now been postponed.

She could not confirm whether the hearing would take place next week.

A man who works for a Moscow-based developer with ties to Mr Trump was identified today as the eighth person to atten dthe Trump Tower meeting.

Lawyer Scott Balber confirmed Ike Kaveladze's name to Reuters after CNN reported that his client had been identified by Mr Mueller's prosecutors and was cooperating in their investigation.

Mr Balber represented Mr Trump himself in the New York businessman's 2013 lawsuit against comedian television host Bill Maher, demanding the $5 million Mr Maher offered to give to charity if Mr Trump could prove his father is not an orangutan.

Mr Kaveladze's LinkedIn profile identifies him as vice president of Crocus Group, a company run by Moscow-based developers Aras Agalarov and his son, Emin, an Azerbaijani-Russian pop star.

The two have ties to the Trump family and helped set up last year's meeting between Mr Trump Jrand Russian lawyer Natalia Veselnitskaya.

Kaveladze was asked to go to the meeting with the understanding that he would be a translator for Ms Veselnitskaya, only to find she had brought her own translator with her, Mr Balber told CNN.

Mr Balber said he also represents the Agalarovs.

He said Mr Mueller's investigators have not interviewed his client or made contact about the Agalarovs.

In addition to Mr Trump Jr, Ms Veselnitskaya, her translator, and Mr Kaveladze, the meeting was attended by Mr Trump’s son-in-law Jared Kushner, Mr Manafort, publicist Rob Goldstone and Russian-American lobbyist Rinat Akhmetshin.

The White House said this evening that President Trump has confidence in Mr Kushner and is aware of no plans to change his role as adviser.