WASHINGTON (Reuters) - The White House counsel’s office has sent a memo instructing President Donald Trump’s aides to preserve materials that could be connected to suspected Russian interference in the 2016 election and related issues, an administration official said on Wednesday.

The official, who spoke on condition of anonymity, confirmed an Associated Press report on the memo. AP, citing administration officials, said the memo was sent on Tuesday.

U.S. intelligence agencies have concluded that Russia sought to influence the presidential election to help Trump defeat Democrat Hillary Clinton.

Congressional committees are investigating Russia’s role in hacking Democratic Party computers and releasing the information publicly. Federal investigators have been looking into possible contacts between Trump advisers and Russia.

Senate Democrats last week asked the White House and law enforcement agencies to keep all materials involving contacts between Trump’s team and Russian officials, AP said. The Senate Intelligence Committee made a similar request, the AP said.