Eight Afghan police officers were killed by gunmen at a police checkpoint in southern Afghanistan, Kandahar's police chief said Friday.

Gunmen lobbed a grenade and sprayed bullets at the officers late Thursday at a checkpoint between the Zahri and Panjwaii district, west of Kandahar, an area known as a base for Taliban insurgents.

The attack also left one officer wounded and two others missing, said provincial police Chief Sumanwal Matiullah.

Afghan police have frequently been attacked by Taliban insurgents, with more than 1,000 officers dying last year.

Elsewhere, a roadside blast next to a police vehicle in Ghazni province killed two officers and wounded five others, said provincial police Deputy Chief Mohammad Zaman. He blamed Taliban militants for the attack.

In eastern Paktika province, Afghan and foreign troops killed seven suspected militants during a clash near the Pakistan border, said Ghamai Mohammadyar, a spokesman for the provincial governor.

The militants had crossed from Pakistan and attacked Afghan border guards in Bermal district, he said. There were no casualties among Afghan and foreign troops.

Afghan and Western officials say Taliban and other militants regularly use Pakistan's lawless tribal areas as bases for attacks against Afghan and foreign troops in the country.

The number of militant attacks has been rising this summer compared to the same period last year, NATO officials say.

With files from the Associated Press