Secretary of Defense James Mattis, during a visit to Afghanistan this week, said U.S. intelligence officials and the Pentagon believe that Russia and Iran are supplying weapons and arms to the Taliban, which, if true, would be a violation of international law.

U.S. military officials say that they have seen an increasing number of Russian-made arms including machine guns and antiaircraft weapons in the hands of Taliban fighters over the past 18 months.

“The Russians seem to be choosing to be strategic competitors in a number of areas,” Mattis said, adding that as far as “the level of granularity and the level of success they are achieving, I think the jury is still out on that.”

“We will have to confront Russia where what they’re doing is contrary to international law or denying the sovereignty of other countries,” he added. “For example, any weapons being funneled in here, unless they are coming through the [Afghan] government, would be a violation of international law.”

Iran is also suspected of supplying arms to Taliban fighters, U.S. officials say.

“Those two countries have suffered losses to terrorism, so I think it would be extremely unwise if they think they can somehow support terrorism in another country and not have it come back to haunt them,” Mattis said.

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