Taliban insurgents detained veteran militia commander Mohammad Ismail Khan on Friday after they seized the western city of Herat, a provincial council member said. The insurgents also captured three more provincial capitals as they press a lightning offensive that is gradually encircling the capital, Kabul.

Khan, who has been leading fighters against the Taliban in recent weeks, was handed over to the insurgents along with the provincial governor and security officials under a pact, provincial council member Ghulam Habib Hashimi told Reuters.

"The Taliban agreed that they will not pose any threat or harm to the government officials who surrendered," Hashimi said.

Khan is one of Afghanistan's most prominent warlords. Known as the Lion of Herat, he battled Soviet occupiers in the 1980s and was a key member of the Northern Alliance whose US-backed forces toppled the Taliban in 2001.

Taliban spokesman Zabihullah Mujahid confirmed that Khan had been detained.

Meanwhile, the capture of Lashkar Gah — Helmand's provincial capital — came after facing some of the heaviest fighting in the last two decades. Hundreds of foreign troops were killed there over the course of the nearly two-decade war.

The insurgents have taken more than a dozen provincial capitals in recent days and now control more than two-thirds of the country just weeks before the US plans to withdraw its last troops.

Attaullah Afghan, the head of the provincial council in Helmand, said that the Taliban captured the provincial capital of Lashkar Gah following heavy fighting and raised their white flag over governmental installations. He says that three national army bases outside of Lashkar Gah remain under the government's control.

Atta Jan Haqbayan, the provincial council chief in Zabul province, said the local capital of Qalat fell to the Taliban and that officials were in a nearby army camp preparing to leave.

Two lawmakers from Afghanistan’s southern Uruzgan province said local officials surrendered the provincial capital, Tirin Kot, to the rapidly advancing Taliban. Bismillah Jan Mohammad and Qudratullah Rahimi confirmed the surrender on Friday. Mohammad said the governor was en route to the airport to depart for Kabul.

Kandahar, Herat captured

The latest advances came hours after the insurgents captured the country’s second and third largest cities in a lightning advance. The seizures of Kandahar and Herat mark the biggest prizes yet for the Taliban.

While Kabul isn’t directly under threat yet, the losses and the battles elsewhere further tighten the grip of a resurgent Taliban, who are estimated to now hold over two-thirds of the country and continue to press their offensive.

With security rapidly deteriorating, the United States planned to send in 3,000 troops to help evacuate some personnel from the US Embassy in Kabul.

Separately, Britain said about 600 troops would be deployed on a short-term basis to support British nationals leaving the country, and Canada is sending special forces to help evacuate its embassy.

Thousands of Afghans have fled their homes amid fears the Taliban will again impose a brutal, repressive government, all but eliminating women’s rights and conducting public executions.

Peace talks in Qatar remain stalled, though diplomats are still meeting, as the US, European and Asian nations warned that any government established by force would be rejected.

“We demand an immediate end to attacks against cities, urge a political settlement, and warn that a government imposed by force will be a pariah state,” said Zalmay Khalilzad, the US envoy to the talks.

Fazel Haq Ehsan, chief of the provincial council in the western Ghor province, said on Friday that the Taliban had entered Feroz Koh, the provincial capital, and that there was fighting inside the city. The Taliban meanwhile claimed to have captured Qala-e Naw, the capital of the western Badghis province. There was no official confirmation.

The Taliban are also on the move in Logar province, just south of Kabul, where they claim to have seized the police headquarters in the provincial capital of Puli-e Alim as well as a nearby prison. The city is some 80 kilometres south of Kabul.

The latest US military intelligence assessment suggests Kabul could come under insurgent pressure within 30 days and that, if current trends hold, the Taliban could gain full control of the country within a few months. The Afghan government may be forced to pull back to defend the capital and just a few other cities in the coming days if the Taliban maintain momentum.

Collapse of Afghan forces

The continuing Taliban onslaught represents a stunning collapse of Afghan forces after the United States spent nearly two decades and $830 billion trying to establish a functioning state after toppling the group in the wake of the September 11 attacks.

The advancing Taliban ride on American-made Humvees and carry M-16s pilfered from Afghan forces.

Afghan security forces and the government have not responded to repeated questions from journalists, instead issuing video communiques that downplay the Taliban advance.

Bill Roggio, a senior fellow at the Foundation for Defence of Democracies, said the Afghan army has rotted from within due to corruption and mismanagement, leaving troops in the field poorly equipped and with little motivation to fight.

The Taliban, meanwhile, have spent a decade taking control of large swaths of the countryside, positioning themselves to rapidly seize key infrastructure and urban areas once President Joe Biden announced the US withdrawal.

The difficulty of moving troops out to the provinces means the government is likely to focus all its efforts on defending the capital.

“Whatever forces are left or remaining that are in the Kabul area and the provinces around them, they’re going to be used for the defence of Kabul,” Roggio said. “Unless something dramatically changes, and I don’t see how that’s possible, these provinces will remain under Taliban control.”

In Herat, Taliban fighters rushed past the Great Mosque in the historic city — a structure that dates to 500 BC and was once a spoil of Alexander the Great — and seized government buildings. Witnesses described hearing sporadic gunfire at one government building while the rest of the city fell silent under the insurgents’ control.

Herat had been under militant attack for two weeks, with one wave blunted by the arrival of warlord Khan and his forces. But on Thursday afternoon, Taliban fighters broke through the city’s defensive lines and later said they were in control.

Afghan lawmaker Semin Barekzai also acknowledged the city’s fall, saying that some officials there had escaped.

In Kandahar, the birthplace of the Taliban, insurgents seized the governor’s office and other buildings, witnesses said.

The governor and other officials fled the onslaught, catching a flight to Kabul, the witnesses added. They declined to be named publicly as the defeat has yet to be acknowledged by the government.

The Taliban had earlier attacked a prison in Kandahar and freed inmates inside, officials said.

Earlier on Thursday, the insurgents raised their flags over the city of Ghazni, which sits on a crucial north-south highway just 130km southwest of Kabul.

In southern Afghanistan, the Taliban’s heartland, heavy fighting continued in Lashkar Gah, where surrounded government forces hoped to hold onto the capital of Helmand province.

Nasima Niazi, a lawmaker from Helmand, criticised ongoing airstrikes targeting the area, saying civilians likely had been wounded and killed.

“The Taliban used civilian houses to protect themselves, and the government, without paying any attention to civilians, carried out airstrikes,” she said.

With the Afghan air power limited and in disarray, aviation tracking data suggested US Air Force B-52 bombers, F-15 fighter jets, drones and other aircraft were involved in the fighting across the country, according to Australia-based security firm The Cavell Group.

US Central Command has acknowledged carrying out several airstrikes in recent days, without providing details or commenting on the concerns over civilian casualties.

A United Nations agency warned that civilians in southern Afghanistan faced cut-off highways and mobile phone outages. It described aid groups as being unable to determine how many people had fled as intense fighting and airstrikes continued there.

In Kabul and surrounding central provinces that remain under government control, the UN’s Office for the Coordination of Humanitarian Affairs said “the security situation remained unstable and unpredictable with elevated conflict and violence.”

Pakistan meanwhile opened the Chaman border crossing for people who had been stranded in recent weeks. The deputy commissioner of Chaman, Captain (retd) Jumma Dad Mandokhail, said the crossing was reopened following talks with the Taliban.

Even as diplomats met in Doha, Qatar on Thursday, the success of the Taliban offensive called into question whether they would ever rejoin long-stalled peace talks with the government in Kabul.

Instead, the group could come to power by force — or the country could splinter into factional fighting as it did after the Soviet withdrawal in 1989.