U.S. President Donald Trump criticized the FBI on Friday for failing to stop leaks of national security information to the media and directed the agency to find those who pass on classified information.

Trump's comments, in a pair of Twitter posts, come amid media reports that the FBI has refused a White House request that it refutes recent stories saying members of Trump's team had been in frequent contact with Russian intelligence agents during the presidential campaign.

Reuters has not verified the reports. The Federal Bureau of Investigation, the nation's top law enforcement agency, did not answer a request for comment on Trump's tweets.

"The FBI is totally unable to stop the national security 'leakers' that have permeated our government for a long time. They can't even find the leakers within the FBI itself. Classified information is being given to media that could have a devastating effect on U.S. FIND NOW," Trump wrote.

The news reports by CNN and The Associated Press said White House Chief of Staff Reince Priebus asked Andrew McCabe, the FBI deputy director, to deny media reports that said Trump campaign advisers had been in frequent contact with the Russians.

A senior administration official told reporters on Friday that an FBI official had told Priebus a recent New York Times story about Russian contacts was not accurate. Priebus asked if the FBI could set the record straight.

The New York Times reported on Feb. 14 that members of Trump's presidential campaign and other associates had repeated contact with senior Russian intelligence officials, citing intercepted communications and other evidence.

Priebus' contact with the FBI came as the bureau conducts ongoing investigations relating to Russian interference in the Nov. 8 U.S. election.

FBI counterintelligence agents are also examining financial transactions by Russian individuals and companies who are believed to have links to Trump associates.

"There are investigations that are going on and those investigations must find out exactly what Russia was doing in the United States," Senator Ben Cardin, the top Democrat on the Senate Foreign Relations Committee, told CNN on Friday.

"We need a complete investigation and we certainly don't want the White House at all trying to influence that investigation."

U.S. Representative John Conyers said any White House attempt to influence the FBI was "deeply troubling."

"The White House is simply not permitted to pressure the FBI to make public statements about a pending investigation of the President and his advisors," Conyers, the top Democrat on the House Judiciary Committee, said in a statement late on Thursday.