Fighting erupted in the western Afghan city of Farah on Tuesday after the Taliban attempted to capture the provincial capital.
Afghan aircraft bombed Taliban positions as residents sought shelter from the explosions and gunfire.
The attack marks the first major assault targeting a city since the Taliban launched their annual spring offensive.
The assault began around midnight, with the militants capturing one urban district and parts of another, said local provincial council member Jamila Amini.
"Heavy fighting continues inside the city and aircraft have just started bombarding Taliban positions," she told AFP Tuesday from inside Farah.
Afghan officials said police special forces from Kandahar and commandos from Herat had also been deployed.
"(The Taliban) will fail," vowed interior ministry spokesman Najib Danish, who said both Afghan and foreign air forces were taking part in the fighting.
Fared Bakhtawer, head of the provincial council, offered a different picture, however, saying that several security checkpoints in Farah were overrun by the Taliban.
Bakhtawer said casualties were high among security forces, but could not provide a precise number.
Mohammad Sarwar Osmani, a lawmaker from Farah province, said strategic security checkpoints around the city were overrun by Taliban and the insurgents were near police headquarters and the governor's offices.
Zabihullah Mujahid, a Taliban spokesman, claimed responsibility. He said fighters launched attacks form multiple directions, after which they overran several checkpoints in the city. Farah borders Helmand province, where the Taliban controls several districts.
The Afghan Defense Ministry said in a statement Tuesday that Afghan security forces were able to repel their attacks.
There was no immediate confirmation from NATO's mission in Kabul.
Defense ministry spokesman Mohammad Radmnish said at least 10 insurgents and two Afghan security force members had been killed so far.
"The situation is under control and will change by the end of the day," he said.
But inside the city residents reported clashes were continuing. "The situation is very bad," Satar Hissaini, a tribal elder in Farah, told AFP.
"Heavy fighting is going on and Taliban are in the city but the police headquarters and NDS (the Afghan intelligence agency) have not fallen to them," he said.
"NDS forces in their HQ are engaged in heavy clashes with the Taliban."
Another provincial council member, Dadullah Qani, confirmed Hissaini's comments, the sound of gunfire and explosions audible as he spoke to an AFP reporter by telephone.
The noise has "filled the city", said one resident who gave his name as Bilal, adding that he could see smoke rising from the direction of a building housing the NDS.
The insurgents released a statement warning residents to stay inside their homes and "stay calm".
Many radio and television channels in the province have stopped broadcasting, fearing for their employees' lives, according to media watchdog Nai.
Farah is a poppy-growing province in an isolated region of Afghanistan. There are plans for a section of the multi-billion-dollar TAPI (Turkmenistan, Afghanistan, Pakistan and India) gas pipeline to traverse it.
Despite security concerns, the Taliban have pledged to cooperate with the gas project.
Farah, which borders Iran, has been the scene of intense fighting in recent years. In 2017 insurgents tried three times to overrun the capital, according to the Afghanistan Analysts Network.
