At least six people were injured in a car bomb explosion targeting a convoy of foreign troops in southern Afghanistan.

Police say the attack occurred Wednesday in Lashkar Gah, the capital of southern Helmand province.

A senior police officer told reporters it was clear the troops were the target of the attack, although it was unclear if any were actually injured in the blast.

Wednesday's violence was the latest in a series of recent attacks against foreigners in Afghanistan after reports surfaced last week that U.S. soldiers improperly disposed of Qurans.

On Monday, a suicide car bomber rammed his explosives-laden car into the gates of a NATO base and airport in the northeastern Afghan city of Jalalabad, killing nine people.

Deadly protests began throughout Afghanistan on February 21 and continued throughout the week, killing more than 30 people, including four U.S. military personnel.

Results of a joint NATO-Afghan probe into the Quran burning are expected to be released in the coming days.

The commander of coalition forces in Afghanistan, U.S. General John Allen, has promised to find those responsible and hold them accountable. If any action is taken against American troops involved, it is expected to come under the U.S. military justice system and not the Afghan legal system.

The joint probe is aimed at determining what led to U.S. soldiers throwing copies of the Quran into a burn pit at Bagram Airbase. NATO officials say a brigadier general has been at the base in Parwan province interviewing people involved and inspecting evidence.

Afghan officials and the U.S. military are also conducting separate investigations into the incident.