The White House has denied that U.S. President Donald Trump was briefed on intelligence that reportedly showed Russia had offered bounties to Taliban-linked militants for killing U.S. soldiers in Afghanistan.

The rewards were purportedly incentives to the guerrillas to target U.S. forces, as Trump tries to withdraw troops from the conflict-torn country – one of the militants' key demands – and end America's longest war.

The claim was first reported by The New York Times on Friday. The newspaper, citing anonymous officials, said Trump was briefed on the findings in March but has not decided how to respond.

Press secretary Kayleigh McEnany said Saturday that "neither the president nor the vice president were briefed on the alleged Russian bounty intelligence."

But she left open the possibility that such intelligence existed.

"This does not speak to the merit of the alleged intelligence but to the inaccuracy of The New York Times story erroneously suggesting that President Trump was briefed on this matter," McEnany said.

However, her denial that Trump was aware of the matter was met with skepticism from Washington's national security fraternity.

"The idea that Trump wouldn't be briefed on Russia putting a bounty on U.S. troops is even crazier than him being briefed and doing nothing," Ben Rhodes, a former national security aide to Trump's predecessor Barack Obama, wrote on Twitter.

The Taliban have denied the report, reiterating that they were committed to an accord signed with Washington in February that paves the way for withdrawing all foreign forces from Afghanistan by next year.

The militants also said homemade explosives account for most fatalities among U.S. forces.

The Taliban said in a statement issued in Kabul that their struggle "is not indebted to the beneficence of any intelligence organ or foreign country."

The group, widely believed to have received years of support from Pakistani intelligence, also denied previous U.S. accusations it was given arms by Russia.

"The Islamic Emirate has made use of weapons, facilities and tools ... that were already present in Afghanistan or are war spoils frequently seized from the opposition in battles," it said.

Russia has also denounced the report, with its embassy in Washington tweeting that the "baseless and anonymous accusations" in the Times story had "already led to direct threats to the life of employees" at its embassies in Washington and London.

"Stop producing #fakenews that provoke life threats, @nytimes," it added in a later tweet.

Russia has a tortured history in Afghanistan, where the former Soviet Union in its final years was bogged down in a devastating fight against militants, then backed by Washington.

The New York Times said there were different theories on why Russia would support Taliban attacks, including a desire to keep Washington bogged down in war.

It said Russia may also be seeking revenge over the U.S. killing of Russian mercenaries in Syria, where Moscow backs Bashar Assad.

According to the newspaper, the Taliban operation was led by a unit known as the GRU, which has been blamed in numerous international incidents, including a 2018 chemical weapons attack in Britain that nearly killed Russian-born double agent Sergei Skripal.

Citing officials briefed on the matter, the Times said the United States determined months ago that a Russian military intelligence unit linked to assassination attempts in Europe had offered rewards for successful attacks last year.

Militants, or armed criminal elements closely associated with them, are believed to have collected some bounty money, the newspaper said.

The White House, the CIA and the Office of the Director of National Intelligence declined requests from Reuters for comment on the Times report.

The paper also said the White House has yet to authorize any steps against Russia in response to the bounties.

Of the 20 Americans killed in combat in 2019, the Times said, it was not clear which deaths were under suspicion.

After nearly 20 years of fighting the Taliban, the United States is looking for a way to extricate itself from Afghanistan and to achieve peace between the U.S.-backed government and the militant group, which controls swathes of the country.

On Feb. 29, the United States and the Taliban struck a deal that called for a phased U.S. troop withdrawal.

U.S. troop strength in Afghanistan is down to nearly 8,600, well ahead of a schedule agreed with the Taliban, in part because of concerns about the spread of the coronavirus, U.S. and NATO officials said in late May.