Afghan authorities say a suicide bomber blew himself up at a police checkpoint in eastern Khost province Saturday, killing 13 people and wounding at least six others.

Provincial officials said the attacker, wearing a suicide vest, was heading for a police checkpoint in the troubled district of Ali Sher, not far from the border with Pakistan. The officials said some of the victims included local civilians who had been meeting with police.

The attack came one day ahead of a NATO summit in Chicago, where heads of state will discuss the security needs of Afghanistan after most foreign combat troops leave or move to support roles by the end of 2014.

In other violence Saturday, NATO said two of its service members died during an insurgent attack, which also took place in the east. A NATO statement did not identify the nationality of the service member killed.