WASHINGTON — Under pressure to show he’s taking the threat of Russian interference seriously, President Donald Trump claimed without evidence Tuesday that Moscow will be “fighting very hard” to help Democrats win in the 2018 midterm elections.

Trump, who has offered mixed messages on Russian interference in U.S. elections — at times even calling it a “hoax” — acknowledged in a tweet that the midterms are a likely target.

“I’m very concerned that Russia will be fighting very hard to have an impact on the upcoming Election,” Trump wrote. But he added “they will be pushing very hard for the Democrats. They definitely don’t want Trump!”

That’s despite Russian President Vladimir Putin saying outright last week, following the leaders’ summit in Helsinki, that he wanted Trump to win in 2016. U.S. intelligence agencies also have determined that Russia interfered in the election to help him win, and the agencies have warned there are ominous signs of more cyberattacks to come.

As Trump tweeted on Tuesday, House Republicans held a hearing on election security in which lawmakers — even some of Trump’s closest GOP allies — strongly criticized Russian interference and pointed to an indictment this month of 12 Russian intelligence officers. The indictment alleges that the Russians broke into Democratic email accounts and tried to penetrate state election systems.

House Oversight and Government Reform Chairman Trey Gowdy noted that the indictment said there is no evidence the vote count was affected, “but that was not likely for a lack of trying.”

Republican Rep. Virginia Foxx of North Carolina criticized Trump directly.

“Unfortunately, the president’s recent comments at the U.S.-Russia summit in Helsinki failed to hold Putin accountable for his attacks on our country’s interests and deter him from future indiscretions,” she said.

Christopher Krebs of the Homeland Security Department told the lawmakers that the intelligence community has observed “continued malign influence operations” into 2018, though they do not appear to be “an effort at the same scope or scale” as in 2016.

Other Republicans were careful to draw a line and not directly disagree with the president.

“I don’t think anyone here denies the fact that Russia attempted to meddle in the elections,” said Rep. Jody Hice, R-Ga. “The issue of meddling is one thing, the issue of the president colluding is another and that is indeed a witch hunt.”

Democrats said Republicans haven’t done enough to keep the vote secure this fall.

“We need all of our Republican colleagues to conduct oversight — not just use strong words,” said Maryland Rep. Elijah Cummings, the top Democrat on the House oversight panel.

Earlier this year, Congress allocated $380 million to assist states with election security upgrades, and most of that money has been disbursed. Democrats want to continue the money through 2019, but Republicans have said new spending isn’t needed.

Meanwhile in the Senate on Tuesday, two senators introduced bipartisan legislation to impose new Russian sanctions, saying the U.S. “must make it abundantly clear that we will defend our nation.”

Also on Tuesday, the White House said the president has “begun the mechanism to remove security clearances” from former national security and intelligence officials who have been critical of his presidency — but later said Trump is still exploring the idea.

White House spokesman Hogan Gidley made the initial comment to reporters traveling aboard Air Force One.

The comment appeared to suggest the president was moving forward with an idea announced by White House press secretary Sarah Huckabee Sanders on Monday. She had said the president was “exploring the mechanisms” to strip clearance from former CIA Director John Brennan, former CIA Director Michael Hayden, James Clapper, the former director of national intelligence, former national security adviser Susan Rice, former FBI Director Jim Comey, and Andrew McCabe, who served as Trump’s deputy FBI director until he was fired in March. McCabe and Comey do not currently have security clearances.

But Gidley later clarified in an email, saying, “Just like Sarah said yesterday,” Trump had “begun looking at the mechanisms to remove security clearances.”

House Speaker Paul Ryan dismissed Trump’s plan to revoke the security clearances as as simply the president’s way of needling his opponents, rather than a serious attack on dissent. Ryan said Tuesday, “I think he’s trolling people, honestly.”

Senate Majority Leader Mitch McConnell, R-Ky., was surprised to learn that some of the former top national security and intelligence officials still had access to classified information. But both GOP leaders were leaving the president’s plan to the White House.

“I don’t have any particular advice to give the president,” McConnell said Tuesday.

Ryan said it is “something that’s in the purview of the executive branch.”

Former CIA directors and other top national security officials are typically allowed to keep their clearances, at least for some period, as a courtesy and so they can be in a position to advise their successors. The clearances are also sometimes required for them to work for government contractors.

McConnell and Ryan also sought to distance themselves from Trump’s invitation for Vladimir Putin to visit Washington in the fall, saying the Russian president is not welcome on Capitol Hill.