A US intelligence investigation into allegations that a secret Russian military intelligence unit paid out bounties to militants in Afghanistan partly concentrated on a suicide vehicle bombing that killed three US Marines, according to officials cited in a New York Times report published Monday.

Some officials reportedly maintained that the intelligence was not concrete — The Times reported that officials were in disagreement about the veracity of the evidence from the bombing and its connection to the Russians.

The latest report comes days after The Times first reported that US intelligence officials assessed that Russia's military intelligence agency paid bounties to Taliban-linked militants to kill NATO troops in Afghanistan.

Since The Times's first report on Friday, several other news organizations have confirmed the intelligence assessment.

The intelligence officials reportedly believed the bounties involve Unit 29155, a branch of Russia's GRU military intelligence agency.

But several news organizations, including The Times, have reported that the intelligence assessment was included in Trump's daily intelligence report as early as February.