MOSCOW • Russia's former ambassador to Washington, Mr Sergei Kislyak, said yesterday that his conversations with former White House national security adviser Michael Flynn had been transparent and focused on matters of US-Russia cooperation.

Mr Kislyak ended his tenure last month but remains a key figure in ongoing US investigations into Moscow's alleged meddling in last year's presidential election.

Mr Flynn, who lasted 24 days in office, was forced to resign in February after it became known that he had failed to disclose the content of conversations he had with Mr Kislyak and misled Vice-President Mike Pence about their meetings.

"We spoke about only the most simple things... but the communication was completely correct, calm, absolutely transparent. In any case, there were no secrets on our side," Mr Kislyak said during a panel discussion on Russian TV. "There are a number of issues which are important for cooperation between Russia and the United States - most of all, terrorism. And that was one of the things we discussed."

His comments come as investigators working for the special counsel, Mr Robert Mueller, recently asked the White House for documents related to Mr Flynn, according to people close to the investigation. Witnesses have also been questioned about whether Mr Flynn was secretly paid by the Turkish government during the final months of the presidential campaign.

Although not a formal subpoena, the document request is the first known instance of Mr Mueller's team asking the White House to hand over records.

In interviews with potential witnesses in recent weeks, prosecutors and Federal Bureau of Investigation agents have spent hours poring over the details of Mr Flynn's business dealings with a Turkish- American businessman who worked last year with Mr Flynn and his consulting business, the Flynn Intel Group. The company was paid US$530,000 (S$721,000) to run a campaign to discredit an opponent of the Turkish government who has been accused of orchestrating last year's failed coup in the country.

Investigators want to know if the Turkish government was behind those payments - and if the Flynn Intel Group made kickbacks to the businessman, Mr Ekim Alptekin, for helping conceal the source of the money.

The line of questioning shows that Mr Mueller's inquiry has expanded into a full-fledged examination of Mr Flynn's financial dealings, beyond the relatively narrow question of whether he failed to register as a foreign agent or lied about his conversations and business arrangements with Russian officials.

REUTERS, NYTIMES