Washington (AFP) - The White House on Tuesday poured cold water on suggestions that Donald Trump met Russia's ambassador while running for the presidency, but indicated it was possible they briefly shook hands.

Amid suggestions that Trump met Sergey Kislyak on April 27 at the Mayflower Hotel in Washington, the White House said it had "no recollection" who Trump shook hands with during a brief reception.

Trump was at the hotel to give a major foreign policy address.

The Russian embassy did not immediately respond to a request for comment.

"Several Ambassadors were present" at Trump's foreign policy speech and pre-speech reception, hosted by the Center for the National Interest, a think tank, White House spokesperson Sarah Sanders told AFP.

"Mr. Trump was at the reception for about five minutes and then went immediately to the podium."

"We have no recollection of who he may have shaken hands with at the reception and we were not responsible for inviting or vetting guests."

Embassies in Washington routinely contact presidential campaigns both Republican and Democrat, trying to give their capitals better insight into the candidates and their views.

But following an election in which US intelligence alleged Moscow tried to aid Trump, Kislyak's contacts have come under intense scrutiny.

Trump's national security advisor Michael Flynn was forced to step down when it was revealed that he misled colleagues about his meetings with the ambassador.

More recently, Attorney General Jeff Sessions has come under fire for telling his Senate confirmation hearing that he "didn't have -- did not have communications with the Russians."

He was forced to correct the record and recuse himself from election-related investigations when it emerged that he had met Kislyak on two occasions.

US media reported that advisors JD Gordon and Carter Page met Kislyak and, separately, that Flynn and Trump's son-in-law and senior White House aide Jared Kushner met Kislyak at Trump Tower in New York last December.

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The Trump White House has repeatedly denied collusion between the campaign and Russian officials.

Trump himself has called the allegations "a total witch hunt."

In a February press conference, Trump insisted that the issue of Russia was "a ruse."

"I have nothing to do with Russia. Haven't made a phone call to Russia in years. Don't speak to people from Russia," he said, while exempting two calls with Vladimir Putin since becoming president.

According to officials, US intelligence agencies and the Federal Bureau of Investigation continue to investigate just how and how much Moscow intruded into US politics.

Four congressional committees have opened probes into the issue.