KABUL, Afghanistan  —  Afghan aviation minister Mirwais Sadiq (search) was assassinated Sunday in the western city of Herat, a government spokesman said.

Unidentified assailants shot Sadiq in his car in Afghanistan's main western city, presidential spokesman Khaleeq Ahmed (search) said. He had no immediate details.

Afghan state television reported that Sadiq's father, Herat (search) governor Ismail Khan (search), escaped a separate attack unhurt. But Ahmed gave a conflicting account, saying Khan had not come under attack.

Authorities were still trying to determine what had happened, the spokesman said. The defense and interior ministers were preparing to travel to Herat to investigate.

State TV said Herat's police and intelligence chiefs were also attacked, but gave no details.

Troops loyal to Khan reportedly surrounded the home of senior military commander Zaher Khan and a militia barracks in the city. Fighting broke out in several places, with several killed and injured, state TV said.

Aid workers in the city contacted by telephone reported shots ringing out Sunday evening and said they had been ordered to hunker down.

Ismail Khan, a former anti-Soviet resistance commander who runs a large private army, has had firm control over Herat since the fall of the Taliban in late 2001. But there have been persistent tensions and occasional factional fighting between his men and those loyal to rival warlords.

Sadiq is the third leading figure — and the second aviation minister — from interim President Hamid Karzai's administration to be assassinated.

Karzai's first civil aviation minister, Abdul Rahman, was assassinated Feb. 14, 2002, at Kabul's airport, in circumstances that remain unclear. Gunmen shot and killed Vice President Abdul Qadir in the capital on July 6, 2002.

Both of those killings remain unsolved.