FILE - President Donald Trump walks with former President Barack Obama on Capitol Hill in Washington.
FILE - President Donald Trump walks with former President Barack Obama on Capitol Hill in Washington.

White House aides are defending President Donald Trump's unsubstantiated claim that former President Barack Obama ordered a wiretap on telephones Trump used at his Trump Tower headquarters in New York.

"There's no question that something happened," White House spokesman Sean Spicer declared Monday. "The question is it, is it surveillance, is it a wiretap, or whatever? There has been enough reporting strongly suggesting something occurred."

But Spicer offered no evidence supporting Trump's claim Saturday in a Twitter comment "that Obama had my 'wires tapped' in Trump Tower just before the victory."

"The president has made it clear he wants Congress to look into this," Spicer said of Trump's wiretap claim.

Intelligence committees in both the Senate and House of Representatives are already investigating the U.S. intelligence community's conclusion that Russia meddled in the presidential election in an effort to help Trump win, and some lawmakers say the Trump claim can be wrapped into those probes.

Spicer's comments came after his assistant, Sarah Huckabee Sanders, told a news talk show that the president was unwilling to accept an assertion by James Comey, the director of the country's top law enforcement agency, the Federal Bureau of Investigation FBI), that Obama did not order an illegal wiretap on Trump.

James Clapper, Obama's national director of intelligence, has also disputed the new president's contention.

Trump adviser Kellyanne Conway told Fox News that "credible news sources" suggested there might have been politically motivated activity during the campaign that has yet to be divulged.

"He is the president of the United States," Conway said of Trump. "He has information that the rest of us do not."

But Trump's wiretapping claim has been widely dismissed by opposition Democrats and some Republicans.

FILE - Rep. Jason Chaffetz, R-Utah, left, confers
FILE - Rep. Jason Chaffetz, R-Utah, left, confers with Rep. Raul Labrador, R-Idaho, as the House Judiciary Committee begins a markup session on the Protecting Access to Care Act on Capitol Hill in Washington.

Congressman Jason Chaffetz, the Republican chairman of the House government oversight panel, told CBS News, "Thus far I have not seen anything directly that would support what the president has said."

Comey, the FBI director, asked the Justice Department to dispute Trump's allegation that Obama ordered the wiretap, although it was not clear why he did not directly dispute the statement himself.  Comey and his department have led the ongoing investigation of Russian influence on last year's election.

Forbidden by law
Under U.S. law, a president cannot order someone's phone to be wiretapped.  Such a move would require approval by a federal judge and be based on reasonable grounds to suspect why a citizen's telephone calls should be monitored.

Clapper, Obama's intelligence chief, said Trump's claim was simply wrong.

"There was no such wiretap activity mounted against the president-elect at the time, or as a candidate or against his campaign," Clapper told NBC's "Meet the Press" on Sunday.

WATCH: Clapper denies wiretap allegation


House Intelligence Committee Chairman Devin Nunes said in a statement Sunday his committee "will make inquiries into whether the government was conducting surveillance activities on any political party's campaign officials or surrogates."

The top Democrat on the committee, Rep. Adam Schiff, said Trump's accusation was based on "conspiracy-based news."

"For a president of the United States to make such an incendiary charge, and one that discredits our democracy in the eyes of the world, is as destructive as it was baseless," Schiff said.

President Donald Trump waves as he arrives at the
President Donald Trump waves as he arrives at the White House in Washington, March 5, 2017, from a trip to Florida.

Trump requests Congressional investigation

Spicer issued a statement Sunday saying the president is requesting the committees to "determine whether executive branch investigative powers were abused in 2016."  

House Democratic Leader Nancy Pelosi said Trump has no proof and is trying to shift conversation from Russia to Obama.

"This is called the wrap-up smear," she told CNN.  "You make up something, then you have the press write about it and then you say everybody's writing about this charge.  It's a tool of an authoritarian to just have you always be talking about what you want them to be talking about."

Senator Marco Rubio told NBC that Trump "will have to answer as to what exactly" he was referring to in making the claim that his phones were tapped.

The publisher of the Newsmax Media website, Christopher Ruddy, a friend of Trump's, wrote Sunday the president told him, "This will be investigated.  It will all come out.  I will be proven right."

Ruddy said he has never seen Trump this angry in a long time.

Russian President Vladimir Putin listens during a
Russian President Vladimir Putin listens during a meeting in Moscow, Russia, Feb. 6, 2017.



Russian meddling
A U.S. intelligence report concluded Russia carried out a campaign at the direction of President Vladimir Putin that used cyberattacks and other methods to influence the U.S. election campaign to help Trump defeat his Democratic challenger Hillary Clinton, a former U.S. secretary of state.

Trump has denied any links to Russia, but several of his aides have met with Moscow's ambassador to Washington, Sergey Kislyak.

Trump ousted his first national security adviser, Michael Flynn, after just 24 days on the job after he lied to Vice President Mike Pence and other top officials about the nature of his own conversations with Kislyak.

Last week, Attorney General Jeff Sessions said he was removing himself from any investigation into the Russian activities after reports emerged that he met twice last year with the ambassador, although he had said at his January confirmation hearing that he did not have communications with the Russians about the Trump campaign.