American officials intercepted electronic data showing large financial transfers from a bank account controlled by Russia’s military intelligence agency to a Taliban-linked account, evidence that supported their conclusion that Russia covertly offered bounties for killing U.S. and coalition troops in Afghanistan.

Though the United States has accused Russia of providing general support to the Taliban before, analysts concluded from other intelligence that the transfers were most likely part of a bounty program that detainees described during interrogations.

Afghan officials this week described a sequence of events that dovetailed with the account of the intelligence. They said that several businessmen who transfer money through the informal “hawala” system were arrested in Afghanistan over the past six months and were suspected of being part of a ring of middlemen who operated between the Russian intelligence agency, known as the G.R.U., and Taliban-linked militants.

The businessmen were arrested in what the officials described as sweeping raids in the north of Afghanistan as well as in Kabul.