KABUL - Taliban insurgents attacked police headquarters and other government buildings in Ghazni in central Afghanistan on Sunday and were threatening to seize control of the city, with the main highway now heavily mined, local lawmakers and residents said.US aircraft conducted at least four air strikes but details of the fighting were unclear as most of the city's telecoms masts were destroyed in fighting over recent days.But lawmakers from Ghazni who managed to talk to some residents said Taliban were in control of much of the city after launching an initial attack in the early hours of Friday."Only the governor's office, police headquarters and intelligence agency's compound are in the hands of the government and Taliban are pushing to take them," said Chaman Shah Ehtemadi, a lawmaker from Ghazni.The attack on Ghazni, a strategic city on the main highway linking Kabul with Afghanistan's south, was the most serious blow to the government since the insurgents came close to overrunning the western city of Farah in May.Mohammad Rahim Hasanyar, a member of the provincial council, said heavy fighting was continuing in several areas of the city and Afghan forces were in defense mode."No one knows what the exact situation is because there is no communication service," he said.There was no confirmed word on casualties. Quoting a hospital official, Afghanistan's 1TV television reported more than 90 members of the security forces and 13 civilians had been killed, with more than 100 wounded. It said there had also been heavy Taliban casualties.