Afghan officials say a female provincial government worker has been gunned down outside her home in the southern city of Kandahar.

A government spokesman says the woman, Rabia Sadat, was shot and killed by a gunman on a motorcycle as she walked to her car on Tuesday morning. Her driver was wounded in the attack.

Sadat worked for the government's social affairs program in Kandahar province. No group has yet claimed responsibility, and officials are not sure why the woman was targeted.

The attack comes a day after militants attacked a supply depot outside the main international military base in southern Kandahar province, killing four private security guards. Six other guards were wounded.

Provincial spokesman Zalmai Ayubi said insurgents armed with explosives Monday stormed the compound operated by Netherlands-based Supreme Group, which supplies fuel to the military. The Taliban claimed responsibility for the attack.

Kandahar is the birthplace of the Taliban and the main city in southern Afghanistan.

Militants have carried out several high-profile killings in the southern city in recent weeks. Last month, a suicide bomber, with explosives hidden inside his turban, assassinated the mayor of Kandahar.

Also last month, a trusted bodyguard shot and killed President Hamid Karzai's half-brother, Ahmad Wali Karzai.

Meanwhile provincial officials in eastern Afghanistan say 12 civilians were wounded by mortars fired during an overnight clash between NATO forces and insurgents in Kunar province.

Violence in Afghanistan is at its worst since the U.S.-led invasion in late 2001, with international troop and Afghan civilian deaths reaching record levels.