The U.S. military says it has carried out two more air strikes against Taliban forces overnight in the northern Afghan city of Kunduz as security forces battle the Islamic militants for control of the city.
The air strikes are in coordination with Afghan security forces, who launched a counterattack against the Taliban on September 29, one day after the militants seized the city from government troops.
A U.S. Army spokesman, Colonel Brian Tribus, said advisers from a U.S.-led coalition of forces still in Afghanistan are "in the Kunduz area advising Afghan security forces."
Afghan security forces said on September 29 that they had retaken government buildings, including the city prison and the provincial police headquarters from Taliban fighters.
But Taliban fighters remained overwhelmingly in control of Kunduz city, which has a population of some 300,000.
Militants launched an offensive to take the city's airport, where officials and security forces had retreated.
Heavy clashes were reported at the entrance to the airport, a strategically valuable operations base that allows the government to fly in troop reinforcements to the battle.
Militants were partially repelled by new air strikes, according to the AFP news agency.
Afghanistan's spy agency said the air strikes near the airport killed Mawlawi Salam, the Taliban's "shadow governor" for the province, along with his deputy and 15 other fighters.
Earlier, NATO confirmed on September 29 that U.S. military planes hit Taliban positions to "eliminate a threat to coalition and Afghan forces operating in the vicinity of Kunduz."
The spokesman would not provide specific details about the air strikes.
The Pentagon expressed confidence in the ability of Afghan security forces to retake Kunduz city.
"Obviously this is a setback for the Afghan security forces. But we've seen them respond in recent weeks and months to the challenges they've faced. And they're doing the same thing in Kunduz right now," Pentagon spokesman Peter Cook told a news briefing on September 29.
Meanwhile, White House spokesman Josh Earnest said Afghan troops are starting to retake some buildings in the city and the United States is providing advisory support.
"The United States strongly condemns the Taliban attacks in Kunduz. We stand with the Afghan people in our commitment to Afghan peace and security," Earnest said, describing the situation in the city as "fluid."
Government troops and officials in Kunduz late on September 28 retreated to the airport after losing control of the city center to an unexpected three-pronged Taliban offensive involving as many as 2,000 militants.
The fall of the city marked the first time since late 2001 that the Taliban has managed to control a provincial capital in Afghanistan.
In Kabul, Afghan security analyst Ali Mohammad Ali described the fall of Kunduz as "a shock, but not a surprise."
Ali described the capture of the city as a "huge political and propaganda victory" for the Taliban and noted that every province in Afghanistan is as fragile as Kunduz.
Kabul residents say they are increasingly worried about the abilities of Afghan troops to provide security across the country without the support of foreign ground forces, most of which withdrew from Afghanistan at the end of 2014.
"We are concerned about this situation," said Kabul resident Hafizullah Khan. "If Kunduz goes, then there's a greater possibility that very soon 10 other provinces will fall into the hands of the Taliban and our people and the country will fall into a crisis and there will be misery."
Ahmed Rashid, a Pakistan-based expert on the Taliban, described the Taliban victory as "a disaster for the Ghani government."
The development, coming just before Ghani prepares to mark one year in office on September 29, raises questions about the discipline and morale of troops in the Afghan National Army -- which was thought to have as many as 7,000 troops posted in districts across Kunduz Province when the Taliban launched its assault.
WATCH: Afghan Security Forces Fight To Retake Kunduz
The seizure of Kunduz also bolsters the credentials of the newly named Taliban leader, Mullah Akhtar Mansur.
The Taliban has faced an internal power struggle since the announcement in July 2015 that the Taliban's founding leader, Mullah Mohammad Omar, has been dead since 2013.
The battle for Kunduz began in April 2015 when Taliban fighters and a small number of allied Central Asian militants who have sworn allegiance to the Islamic State militant group launched an offensive across much of the province.
In the initial days of that offensive, the Taliban managed to seize high ground on the northwestern portion of the provincial capital known as Gul Tepe.
Government forces have been unable to dislodge the Taliban from the city's northwestern high ground throughout the summer, despite NATO air strikes and deployments of government reinforcements.
The urban areas seized by the Taliban on September 28 were the low lying areas of the city between the Kunduz and Khanabad rivers.
Government forces claimed they were starting to recapture government buildings on September 29, but not before the Taliban had reportedly managed to release more than 600 prisoners from the city's prison, including about 100 captured Taliban fighters.
Relatives of prisoners who were freed by the Taliban told RFE/RL's Radio Free Afghanistan that they were forcing others they had released to fight for the militant movement.
Taliban fighters were reportedly burning some government buildings early on September 29 before Kabul's counteroffensive was launched.
Residents of Kunduz told reporters by telephone that Taliban fighters were reinforcing strategic positions within the city on September 29 and had blocked all roads leading out of the city.
They also reported that the Taliban on September 29 was searching for government workers in Kabul who did not manage to slip out of the city overnight or escape to Kunduz airport the day before.
Taliban spokesman Zabihullah Mujahid vowed that the militant advance was just "the beginning," and that the Taliban aims to capture the Afghan capital, Kabul.
"You will see how we capture Kabul," he said, vowing to "hang in the public squares" the elected government officials of Afghanistan.
The U.S. Embassy in Kabul issued a travel warning to its citizens on September 29, saying "the security situation in Afghanistan is extremely unstable, and the threat to all U.S. citizens in Afghanistan remains critical."
The statement added that "U.S. citizens currently visiting or residing in Afghanistan may wish to consider departing."