A series of blasts killed at least two civilians and wounded several others Saturday in Afghanistan's main southern city, the scene of several recent deadly attacks on police.

Helicopters patrolled above the city as NATO and Afghan troops were deployed to seal off the attack sites. Ambulances with sirens wailing ferried victims to local hospitals.

In one attack, a motorized rickshaw carrying explosives detonated behind police headquarters in the center of the city, said Zelmai Ayubi, spokesman for the governor of Kandahar province. One bystander was killed and three others wounded, Ayubi said.

On the eastern side of the city, insurgents attacked an oil tanker with gunfire, causing it to explode. One civilian was killed and at least two others were wounded.

A rocket fired by militants slammed into a prison compound in the city's west, police said. No casualties were immediately reported. Another explosion went off in the city's business district, also in the west. Details were not immediately available.

Kandahar city has been a target for militants this month. Two explosions killed nine people and wounded two dozen others on Oct. 6. Three blasts just minutes apart killed three Afghan police officers in the city Oct. 5.