WASHINGTON (Reuters) - President-elect Donald Trump voiced new doubts on Wednesday that Russian hackers attempted to influence the U.S. election on his behalf, saying WikiLeaks had denied Moscow was behind documents it made public during the campaign.

U.S. President-elect Donald Trump delivered brief remarks to reporters at the Mar-a-lago Club in Palm Beach, Florida, U.S. December 28, 2016. REUTERS/Jonathan Ernst

Trump, writing on Twitter, continued to raise questions about the findings by U.S. intelligence agencies that Russia was behind a series of leaks that embarrassed Democratic candidate Hillary Clinton’s campaign before the Nov. 8 vote.

The tweets prompted White House spokesman Josh Earnest to ask, “Who are you going to believe?”

Documents stolen from the Democratic National Committee and John Podesta, Clinton’s campaign manager, were leaked to the media in advance of the election. One email showed the Clinton campaign received a question in advance of a town hall forum.

Trump resumed sending notes on Twitter about the hacking issue on Wednesday, saying, “(WikiLeaks founder) Julian Assange said ‘a 14 year old could have hacked Podesta’ - why was DNC so careless? Also said the Russians did not give him the info!”

Trump also quoted Assange as telling Fox News that U.S. media coverage of the matter was “very dishonest.”

Asked about the tweets, Earnest said the president-elect’s public comments have pitted the Russians and Assange against 17 U.S. government intelligence agencies, outside cyber experts and lawmakers from both parties.

“There’s a pretty stark line that’s been drawn, and the president-elect will have to determine who he’s going to believe,” he said at a daily news briefing.

Vice President-elect Mike Pence defended Trump as simply voicing a “very sincere and healthy American skepticism about intelligence conclusions” he has been hearing.

“Given some of the intelligence failures of recent years, the president-elect has made it clear to the American people that he’s skeptical about conclusions from the bureaucracy,” Pence told reporters at the U.S. Capitol.

But the top ranking elected Republican, House of Representatives Speaker Paul Ryan, had harsh words for Assange, whose group released the hacked emails. “I think the guy’s a sycophant for Russia, he leaks, he steals data and compromises national security,” Ryan told radio host Hugh Hewitt.

President Barack Obama last month ordered an investigation into malicious cyber activity and foreign intervention in the 2016 presidential election before he leaves office on Jan. 20. Earnest said the intelligence community will meet the deadline with ample time to spare.

Separately, five Democratic U.S. senators introduced legislation urging the creation of an independent, nonpartisan commission to investigate any Russian interference in the election. Several lawmakers, including a few of Trump’s fellow Republicans, have backed calls for an investigation.

Trump and Pence were scheduled to receive a briefing from intelligence officials on the hacking issue on Friday.