WASHINGTON – U.S. President Donald Trump said Sunday he had never been told about reports that a Russian military intelligence unit was secretly offering bounties to Taliban militants in Afghanistan to kill U.S. soldiers.

Trump scoffed at a New York Times report that U.S. intelligence officials had concluded months ago that the Russian unit, which has been linked to assassination attempts and covert operations in Europe aimed at destabilizing the West, had carried out the mission in Afghanistan last year and that he had been briefed about it in late March.

On Twitter, he said, “Nobody briefed or told me,” Vice President Mike Pence or White House chief of staff Mark Meadows “about the so-called attacks on our troops in Afghanistan by Russians, as reported through an ‘anonymous source’ by the Fake News @nytimes. Everybody is denying it & there have not been many attacks on us.”

Twenty American troops were killed in Afghanistan last year, but it was not known which killings might have been linked to the alleged Russian bounties.

Critics have accused Trump of often being deferential to Russian President Vladimir Putin during his 3 ½-year term in the White House. But Trump tweeted, “Nobody’s been tougher on Russia than the Trump Administration,” contending that Russia “had a field day” under former President Barack Obama and Vice President Joe Biden, Trump’s opponent in the national November presidential election.

The U.S. leader challenged the newspaper to “reveal its ‘anonymous’ source. Bet they can’t do it, this ‘person’ probably does not even exist!”

Both Russia and the Taliban denied the report of the bounties, with Moscow calling them “baseless and anonymous accusations.” The Russian embassy in Washington said the New York Times report had “already led to direct threats” on the lives of employees at Russian embassies in Washington and London.

A spokesman for the Taliban, Zabihullah Mujahid, rejected the report that the insurgents have “any such relations with any intelligence agency” and called the newspaper report an attempt to defame them.

“These kinds of deals with the Russian intelligence agency are baseless — our target killings and assassinations were ongoing in years before, and we did it on our own resources,” he said. “That changed after our deal with the Americans, and their lives are secure, and we don’t attack them.”

Earlier this year, the U.S. and the Taliban signed an “agreement for bringing peace” to Afghanistan after more than 18 years of conflict. The U.S. and NATO allies agreed to withdraw all troops by next year if the militants uphold the deal.

Trump said it had been a “long and hard journey” in Afghanistan, but that, “It’s time after all these years to bring our people back home.”

Despite Trump’s denial of the alleged bounties, one of the top-ranking Republican lawmakers in Congress, Congresswoman Liz Cheney, voiced concerns about the report.

“If reporting about Russian bounties on US forces is true, the White House must explain: 1. Why weren’t the president or vice president briefed?” she said on Twitter. She asked whether the information was in Trump’s daily presidential briefing.

“Who did know and when? What has been done in response to protect our forces & hold Putin accountable?” said Cheney, the daughter of former U.S. Vice President Richard Cheney.

John Bolton, Trump’s former national security adviser who now contends in a new book that the president is unfit to run the country, told CNN that Trump’s tweets about the alleged bounties show that he was not concerned about “the security of our forces,” but “whether he was paying attention” to the intelligence report he supposedly was given.