WASHINGTON - US President Donald Trump's son-in-law, Jared Kushner, is willing to cooperate with federal investigators looking into ties between Russia and the Trump campaign, his attorney said.

The statement from attorney Jamie Gorelick was issued on Thursday amid reports that the FBI was investigating meetings Kushner had in December with Russian officials.

"Kushner previously volunteered to share with Congress what he knows about these meetings. He will do the same if he is contacted in connection with any other inquiry," the statement said.

Meanwhile, the chairman of the House oversight committee asked the FBI to turn over more documents about former director James Comey's interactions with the White House and Justice Department, including materials dating back nearly four years to the Obama administration.

The FBI and the oversight committee as well as several other congressional panels are looking into Russian meddling in the 2016 presidential election and possible connections between Russia and the Trump campaign. Trump fired Comey on May 9 amid questions about the FBI's investigation, which is now being overseen by special counsel Robert Mueller, a former FBI director.

NBC News and The Washington Post first reported that the FBI's ongoing investigation includes a look at Kushner, which would place the probe inside the White House.

Kushner, a key White House adviser, had meetings late last year with Russia's ambassador to the US, Sergey Kislyak, and Russian banker Sergey Gorkov.

The Post story cited anonymous "people familiar with the investigation", who said the FBI investigation does not mean that Kushner is suspected of a crime.

Ap - Xinhua