A Taliban attack on a mosque and dining facility at Camp Shaheen outside Mazar-e-Sharif in Afghanistan on Friday claimed the lives of more than 140 Afghan soldiers, with a final death toll still being tallied, prompting Afghanistan’s defense minister and army chief of staff to resign their positions.

“2017 is going to be another tough year for the valiant Afghan security forces and the international troops who have stood, and will continue to stand, shoulder to shoulder with Afghanistan against terrorism,” American Secretary of Defense, James Mattis, said upon his arrival in Afghanistan on Monday.  The storied Marine general turned Defense Secretary is in the country as a part of ongoing efforts to craft a new Afghan strategy against the likes of the Taliban.

Mattis told journalists that he was “under no illusions” about the problems facing the country, which may include an influx of weaponry reaching Taliban hands from American political opponent, Russia.  Even General John Nicholson, the head of U.S. and international forces in Afghanistan who recently testified before Congress that more troops were needed to end the stalemate against terrorists in Afghanistan, said he was “not refuting” reports that Russia was providing support, including weapons, to the Taliban.

A senior defense official who spoke under the condition of anonymity told reporters on Monday that intelligence indeed shows that Russia has been providing money and automatic weapons to the Taliban.  Russia has denied any such wrong doing, but claims they maintain open lines of communication with Taliban leaders in order to continue to push for peace talks.  They have also been openly critical of the United States and its ongoing efforts in the country.