WASHINGTON (AP) -- Key members of Congress say they will honor President Donald Trump's request to investigate his unsubstantiated claim that Barack Obama overstepped his authority as president and had Trump's telephones tapped during the election campaign. A U.S. official said the FBI has asked the Justice Department to dispute Trump's allegation, though no such statement has been issued.
Obama's intelligence director also said no such action was ever carried out.
Trump's startling claim of presidential abuse of power, made without evidence in a series of tweets early Saturday, capped a week in which the positive reaction to his address to Congress quickly evaporated amid the swirl of allegations --- and revelations --- about contacts between Trump aides and Russia's ambassador to the U.S., both during and after a presidential election Russia is believed to have meddled in.
Trump is said to be frustrated by his senior advisers' inability to tamp down the Russia issue. Compounding the situation was the revelation last week that former U.S. senator and now Attorney General Jeff Sessions, an early Trump campaign supporter, had met twice with the Russian official but didn't disclose that to lawmakers when he was asked about it during his Senate confirmation hearing.
Separately, an Indiana newspaper reported that Vice President Mike Pence used personal email to conduct state business when he was governor of Indiana. The revelation recalled the use of personal email by Trump's 2016 opponent, Hillary Clinton, when she was secretary of state. The issue dogged Clinton for most of the presidential campaign.
"It's sort of like getting nibbled to death by ducks," said Rutgers political science professor Ross Baker.
The House and Senate intelligence committees, and the FBI, are investigating the contacts, and Trump demanded Sunday that they broaden the scope of their inquiries into Russian meddling in the 2016 election to include Obama's potential abuse of his executive powers.
Senate Intelligence Committee Chairman Richard Burr, R-N.C., said in a statement that the panel "will follow the evidence where it leads, and we will continue to be guided by the intelligence and facts as we compile our findings."
Rep. Devin Nunes, R-Calif., chairman of the House Intelligence Committee, said in a statement that the committee "will make inquiries into whether the government was conducting surveillance activities on any political party's campaign officials or surrogates."
Trump's request carries some risk, particularly if the committees unearth damaging information about him or his associates. Committee Democrats will have access to the information and could wield anything negative against the president. Asking Congress to conduct a much broader investigation than originally envisioned also ensures the Russia issue will hang over the White House for months.
Trump claimed in a series of unsubstantiated tweets Saturday that his predecessor had tried to undermine him by tapping the telephones at Trump Tower, the New York skyscraper where Trump based his campaign and transition operations, and maintains a home.
Obama's director of national intelligence, James Clapper, said nothing matching Trump's claims had taken place.
"Absolutely, I can deny it," said Clapper, who left government when Trump took office. Other Obama representatives also denied Trump's allegation, which the FBI has asked the Justice Department to dispute, a U.S. official told The Associated Press on Sunday. The official wasn't authorized to discuss the request by name and spoke on condition of anonymity.
The department, however, has issued no such statement. DOJ spokeswoman Sarah Isgur Flores declined to comment Sunday, and an FBI spokesman also did not comment.
The New York Times reported that senior American officials say FBI Director James Comey has argued that the Justice Department must correct the claim because it falsely insinuates that the FBI broke the law.
White House press secretary Sean Spicer said Trump's instruction to Congress was based on "very troubling" reports "concerning potentially politically motivated investigations immediately ahead of the 2016 election." He did not elaborate.
Spicer said the White House wants the congressional committees to "exercise their oversight authority to determine whether executive branch investigative powers were abused in 2016." He said there would be no further comment until the investigations are completed.
Spicer's chief deputy, Sarah Huckabee Sanders, said she thinks Trump is "going off of information that he's seen that has led him to believe that this is a very real potential."
Josh Earnest, who was Obama's White House press secretary, said presidents do not have authority to unilaterally order the wiretapping of American citizens, as Trump has alleged was done to him. FBI investigators and Justice Department officials must seek approval from a federal judge for such a step. Earnest accused Trump of leveling the allegation to distract from the attention being given to the Russia issue.
Democrats on the House Judiciary Committee said they will ask the White House for details about reports of contacts between the White House and the Justice Department concerning the FBI's review of whether the Russian government unlawfully influenced the U.S. presidential election.
Trump said in the tweets that he had "just found out" about being wiretapped. Unclear was whether he was referring to having learned through a briefing, a conversation or a media report. The president in the past has tweeted about unsubstantiated and provocative reports he reads on blogs or conservative websites.
The tweets stood out, given the gravity of the charge and the sharp personal attack on the former president. Trump spoke as recently as last month about how much he likes Obama and how much they get along, despite their differences.
"How low has President Obama gone to tapp my phones during the very sacred election process. This is Nixon/Watergate. Bad (or sick) guy!" he tweeted, misspelling 'tap.'
Obama spokesman Kevin Lewis said a "cardinal rule" of the Obama administration was not to interfere in Justice Department investigations. Lewis said neither Obama nor any White House official had ever ordered surveillance on any U.S. citizen. "Any suggestion otherwise is simply false," Lewis said.
Clapper appeared on NBC's "Meet the Press," and Sanders and Earnest were on ABC's "This Week."