Washington: Further contacts between the Russian ambassador Sergey Kislyak and the Trump camp, including Trump family member Jared Kushner, have emerged even as Attorney-General Jeff Sessions battles a storm of controversy stemming from his meetings with the ambassador.

Michael Flynn, then Donald Trump's incoming national security adviser, had a previously undisclosed meeting with the Russian ambassador in December to "establish a line of communication" between the new administration and the Russian government, the White House said on Thursday.

Jared Kushner, Trump's son-in-law and now a senior adviser, also participated in the meeting at Trump Tower with Kislyak. But among Trump's inner circle, it is Flynn who appears to have been the main interlocutor with the Russian envoy. The two were in contact during the campaign and the transition, Kislyak and current and former US officials have said.

The extent and frequency of Flynn-Kislyak contacts remains unclear, but the disclosure of the meeting at Trump Tower adds to the emerging picture of how the relationship between Trump's incoming team and Moscow was evolving to include some of the president-elect's most trusted advisers.