KANDAHAR, (Reuters) – At least one person was killed and four wounded when a bomb left on a parked motorcycle exploded outside an Afghan police compound in Kandahar city, authorities said on Saturday.

“We were about to defuse it when it exploded,” said Zalmay Ayubi, a spokesman for the provincial governor’s office in Kandahar, where U.S. troops are fighting a campaign to drive the Taliban out of districts long seen as their strongholds.

Mohammad Rasool, a doctor at a local hospital, said one person had been killed and four wounded in the blast.

Casualties in the Afghanistan war are at their highest since the Taliban were ousted by U.S.-backed forces in 2001. More than 2,000 foreign troops have been killed since then as the insurgents extended attacks beyond their southern heartland.