KABUL, Afghanistan — Taliban insurgents entered the southeastern Afghan city of Ghazni before dawn on Friday, and within hours they claimed to have much of the provincial capital under their control. If confirmed, the rout would be the insurgents’ most important strategic gain in years.
Government officials denied the city had fallen, but they conceded that the insurgents were within 300 yards of the governor’s office and police headquarters.
“Fighting is ongoing but the whole city has not been taken by the Taliban,” Mohammad Arif Noori, the spokesman for Ghazni’s governor, said by telephone. “We will not allow them to take the city.”
Zabihullah Mujahid, the Taliban spokesman, said on Twitter that the insurgents had infiltrated every part of the city. “Hundreds of Mujahedeen entered the city, captured the police headquarters and all six police districts and an important military base, Bala Hesar,” Mr. Mujahid said in an emailed statement.
“Attacks are underway on the governor’s office, the N.D.S. headquarters and other government offices,” he said, using the acronym for the National Directorate for Security, the Afghan intelligence agency.
The Ghazni attack was the second determined assault on an Afghan city this year. In May, insurgents overran the western city of Farah, but they left a day later amid counterattacks from the Afghan government and American airstrikes.
The only other Afghan city to have fallen to the Taliban was Kunduz, in the far north, which insurgents briefly occupied twice, in 2015 and 2016. Neither Farah nor Kunduz were as strategically important as Ghazni.
Ghazni, a city of 150,000 and the capital of Ghazni Province, sits on the ring road, the important north-south highway connecting Kabul and Kandahar. Travelers in Kandahar on Friday reported being turned back because the insurgents had blocked the highway. If the Taliban took Ghazni and held it, they would essentially have cut off the south from the north.
Mr. Mujahid said the insurgents had closed the ring road to prevent reinforcements from reaching Ghazni.
Brig. Gen. Mohammad Radmanish, the spokesman for the Afghan Ministry of Defense, denied Ghazni was under any serious threat. “It is just propaganda by the Taliban. The whole city is under the control of Afghan forces,” he said, adding that not a single Afghan soldier had been killed in the fighting.
Many areas of Ghazni Province have been heavily contested by the insurgents in recent years, but this is the first serious attempt to take the provincial capital.
Mr. Noori, the governor’s spokesman, said that one policeman had been killed and seven other officers had been wounded. Reinforcements began arriving in the city on Friday, but the government was hampered in carrying out airstrikes because the insurgents were operating in civilian neighborhoods.
“Commando forces are responding to the Taliban attack but we are not carrying out airstrikes to prevent civilian casualties,” Mr. Noori said. He accused the Taliban of using the civilian population as human shields. Eight civilians had been wounded so far, he said.