A car carrying civilians was driving nearby and was caught up in the blast. In addition to the deaths, one police officer and 11 civilians were wounded, including six children, Noorzai said.

Panjwai is on the edge of Kandahar city, the main city in the south and the focus of a major military push starting this summer to drive the Taleban out of their southern strongholds. NATO has widely publicized the coming offensive as a combination of military strikes and government-boosting programs it hopes will win over the population.

The Taleban, meanwhile, have launched a series of high-profile attacks as part of their own summer offensive against the Afghan government and international forces. The area in and around Kandahar city has become particularly violent in recent months, with regular bomb attacks and assassinations of people seen as allied with the government.

No one immediately claimed responsibility for Sunday's attack, which came a day after a bomb exploded outside the provincial governor's office in Kandahar city. That bomb killed one police officer and wounded at least 14 civilians.

In neighboring Uruzgan province, police said they killed more than 20 suspected insurgents in two operations in the past 36 hours. In one of those operations, in Charchino district, 14 militants were killed including an area commander, said Gen. Juma Gul Himmat, the provincial police chief.