A group of US soldiers got caught up in a roadside bombing in the Ghazni Province of Afghanistan on Tuesday. At least three US soldiers were confirmed killed, and three others wounded. Another American, a contractor, was also wounded.

This is the single deadliest incident for US troops in Afghanistan in 2018. High casualty incidents were more common earlier in the war, but US troops are less often on the front lines, or in places where they’re likely to directly face such attacks.

The condition of the wounded remains unclear, though officials did say that they have been evacuated and are receiving treatment. In general, details are limited until the families of the casualties are notified.

Taliban forces have been heavily contesting Ghazni Province in recent weeks, and that may be why more US forces are present in the area. This is the second case of US deaths in Afghanistan in less than a week, with another soldier having died of wounds in a gunfight in Nimruz Province on Saturday.