Hundreds of Taliban fighters have stormed a strategic district in an Afghan province not far from the capital, killing dozens of people in five days of fighting and they could capture the area, officials said on Friday.
The Ghazni provincial government has lost contact with police in the province's western district of Ajrestan, said Asadullah Safi, deputy police chief of the area.
Ghazni is southwest of the capital. The main highway linking Kabul to southern Afghanistan, where the Taliban have been making advances in recent months, passes through the province.
"If there is no urgent help from the central government, the district will collapse," Safi said.
The battle for Ajrestan illustrates the grave challenges facing Afghanistan's new president and the security forces in holding territory as foreign combat troops prepare to leave at the end of the year.
No longer pinned down by U.S. air cover, Taliban fighters are attacking Afghan military posts in large numbers with the aim of taking and holding ground.
Heavy fighting was continuing in Ajrestan on Friday. Safi said a suicide car bomber attacked a police checkpoint early in the day before provincial authorities completely lost contact with the district.
The attack by an estimated 700 Taliban fighters began about five days ago and early reports were that more than 100 people had been killed, including 15 who were beheaded by the militants, said provincial deputy governor Ahmadullah Ahmadi.
The militants have been focusing on regaining important opium-growing areas, such as the southern province of Helmand, and areas where they have traditionally enjoyed support, such as Kunduz province in the north.
Control of Ghazni's mountainous Ajrestan district, about 200 km (125 miles) from Kabul, could provide the Taliban with a launching point for attacks in two bordering provinces and along the crucial artery connecting the capital to Afghanistan's second city of Kandahar in the south.
Call for help
The growing Taliban threat is likely to be the most urgent challenge for the new, U.S.-brokered government of national unity between President-elect Ashraf Ghani and his former rival Abdullah Abdullah.
Provincial authorities have appealed for help from the central government in Kabul, where Ghani is in the process of taking over the presidency from Hamid Karzai.
"We have asked repeatedly for helicopters to evacuate the wounded, but so far nothing has been done," Ahmadi said.
However, a regional spokesman for the Afghan army, Nazif Sultani, said on Friday reinforcements had been sent to the district the previous day. He said he had no further information.
Months of deadlock over a disputed election and uncertainty over whether any U.S. troops will remain beyond this year has battered morale among Afghan security forces.
"Peace with the Taliban requires a strong government. At the moment the Taliban think they can fight in every province and they believe they can overthrow the government," said Haji Mohammad Mohaqiq, Abdullah's running mate and the leader of Afghanistan's ethnic Hazara minority.
"Without international support it will be hard to provide security ... The example of Ajrestan district shows that without international commitment of troops, it will be difficult to handle the Taliban."