WASHINGTON (Reuters) - The US House of Representatives intelligence committee will investigate allegations of collusion between Donald Trump's presidential campaign and Russia, the top Democrat on the panel said on Wednesday (March 1).

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

"We have reached a written agreement, the minority and the majority in the House intelligence committee, that we will investigate allegations of Russian collusion with the Trump campaign," Democratic Representative Adam Schiff said on MSNBC.

The committee said in a statement that its Republican chairman, Devin Nunes, and Schiff had agreed that their investigation will seek answers to questions including: "Did the Russian active measures include links between Russia and individuals associated with political campaigns or any other US Persons?"

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 separately 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.

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.