WASHINGTON (Reuters) - Hillary Clinton’s campaign chairman, John Podesta, on Tuesday appeared before the U.S. House of Representatives Intelligence Committee, which has begun interviewing witnesses in its probe of how Russia may have influenced the 2016 election.

FILE PHOTO - John Podesta, chairman of the 2016 Hillary Clinton presidential campaign, addresses the crowd at Democratic U.S. presidential nominee Hillary Clinton's election night rally in New York, U.S., November 9, 2016. REUTERS/Carlos Barria

Committee members declined to comment on the discussion to reporters as they left the panel’s secure hearing room. Podesta stopped and commented briefly.

“They asked me to come forward to give to the best of my knowledge what I knew about that, and I was happy to cooperate with the committee in their investigation of Russian interference with the democratic process in the United States,” he said.

Republican President Donald Trump, who defeated Clinton in the election, recently has accused former Democratic President Barack Obama of doing too little to address Russian cyber attacks while he was still in the White House.

On Monday, Trump demanded on Twitter that investigators apologize for looking to Russian interference and possible collusion with his campaign. He accused Obama of having “colluded or obstructed,” without providing evidence. [nL1N1JN12O]

Asked whether he thought Obama had done enough, Podesta said, “I think the president and the entire administration were dealing with an unprecedented incidence of the weaponization of the fruits of Russian cyber activity and making the best judgments they could on behalf of the American people.”

During the 2016 campaign, hackers penetrated the Democratic National Committee’s email server and separately stole emails from Podesta’s personal account. The emails were then posted online and used to embarrass Clinton, including by Trump, who frequently used their content as political ammunition.

U.S. intelligence agencies have concluded that Russia was behind the hacking and that it was seeking to boost Trump’s chances of winning the White House.

Russia has denied trying to influence the election, and Trump has dismissed such allegations as sour grapes by Democrats and their supporters unable to come to terms with his surprise victory in November.

The House intelligence panel is conducting one of several investigations into Russian meddling in the election and possible collusion with members of Trump’s campaign, as is Department of Justice Special Counsel Robert Mueller.[nL1N1IC249]

The House panel began bringing in witnesses for interviews this week, and a few more are expected before lawmakers leave Washington by Friday for their weeklong July 4 holiday recess.