Afghan MPs were warning that the death toll is continuing to rise today after yesterday’s infiltration and attack of an Afghan military base near Mazar-e Sharif, which was initially reported to have killed around 50 soldiers and is now shaping up to be the single deadliest Afghan attack on the military in the entire war.

Taliban attackers in Afghan military vehicles wearing uniforms got through the external checkpoint to the base, bombing their way past a secondary checkpoint, then launched shooting attacks against the base mosque, just finishing Friday prayers, and the cafeteria, which was just starting to serve lunch. At least 140 are now confirmed dead, with some warning the toll could ultimately exceed 200.

Afghan officials are reeling after the incident, both because the area around the base was long considered an unusually calm part of Afghanistan, and because it took only a handful of Taliban to kill such a huge number of Afghan soldiers in the surprise attack.

The Taliban reported 10 attackers involved in the strike, as well as four Afghan soldiers who were on the base working as infiltrators who led the rest of the attackers to the places with the most people. Considering that some 3,000 to 4,000 soldiers were in the mosque at the time of the attack, some are saying the toll could easily have been a lot worse.

The Afghan government has ordered a day of mourning after the attack, and has promised an investigation to try to find the soldiers who helped the Taliban. Given the omnipresence of Taliban infiltrators throughout security forces, however, rooting out these specific ones may be an enormous task.