Taliban fighters entered Kabul on Sunday and sought the unconditional surrender of the central government, officials said, as Afghans and foreigners alike raced for the exit, signalling the end of a 20-year Western experiment aimed at remaking Afghanistan.The beleaguered central government, meanwhile, hope for an interim administration, but increasingly had few cards to play.

Civilians fearing that the Taliban could reimpose the kind of brutal rule that all but eliminated women's rights rushed to leave the country, lining up at cash machines to withdraw their life savings.Helicopters buzzed overhead, some apparently evacuating personnel at the US Embassy. Several other Western missions were also preparing to get staff out.

In a stunning rout, the Taliban seized nearly all of Afghanistan in just over a week, despite the hundreds of billions of dollars spent by the US and NATO over nearly two decades to build up Afghan security forces. Just days earlier, an American military assessment estimated it would be a month before the capital would come under insurgent pressure.

Instead, the Taliban swiftly defeated, co-opted or sent Afghan security forces fleeing from wide swaths of the country, even though they had some air support from the U.S. military.On Sunday, the insurgents entered the outskirts of Kabul but apparently remained outside of the city's downtown. Sporadic gunfire echoed at times though the streets were largely quiet.Workers fled government offices, and smoke rose over the city as embassy staff burned important documents.

Taliban spokesman Suhail Shaheen told Qatar's Al-Jazeera English satellite news channel that the insurgents are awaiting a peaceful transfer of Kabul city. He declined to offer specifics on any possible negotiations between his forces and the government.But when pressed on what kind of agreement the Taliban wanted, Shaheen acknowledged that they were seeking an unconditional surrender by the central government.

Taliban negotiators headed to the presidential palace Sunday to discuss the transfer, said an Afghan official who spoke on condition of anonymity for fear of reprisals. It remained unclear when that transfer would take place.

The negotiators on the government side included former President Hamid Karzai and Abdullah Abdullah, the head of the Afghan National Reconciliation Council, an official said. Abdullah long has been a vocal critic of President Ashraf Ghani, who long refused giving up power to get a deal with the Taliban.

The official, who spoke on condition of anonymity to discuss details of the closed-doors negotiations, described them as tense.

Acting Defense Minister Bismillah Khan sought to reassure the public that Kabul would remain secure. The insurgents also tried to calm residents of the capital, insisting their fighters wouldn't enter people's homes or interfere with businesses.They also said they'd offer an amnesty to those who worked with the Afghan government or foreign forces.

No one's life, property and dignity will be harmed and the lives of the citizens of Kabul will not be at risk, the insurgents said in a statement. But they also warned no one to enter the area around the capital.

Despite the pledges, panic set in as many rushed to leave the country through the Kabul airport, the last route out of the country as the Taliban now hold every border crossing.Rapid shuttle flights of Boeing CH-47 Chinook helicopters near the US Embassy began a few hours later after the militants seized the nearby city of Jalalabad which had been the last major city besides the capital not in Taliban hands. Diplomatic armored SUVs could be seen leaving the area around the post.

The US State Department did not immediately respond to questions about the movements. However, wisps of smoke could be seen near the embassy's roof as diplomats urgently destroyed sensitive documents, according to two American military officials who spoke on condition of anonymity because they were not authorised to discuss the situation.The smoke grew heavier over time in the area, home to other nation's embassies as well.

Sikorsky UH-60 Black Hawk helicopters, which typically carry armed troops, later landed near the U.S. Embassy. The U.S. decided a few days ago to send in thousands of troops to help evacuate some personnel from its embassy.

At Kabul International Airport, Afghan forces abandoned the field to Western militaries, said a pilot who spoke on condition of anonymity to discuss security matters.

Ghani, who spoke to the nation Saturday for the first time since the offensive began, appeared increasingly isolated. Warlords he negotiated with just days earlier have surrendered to the Taliban or fled, leaving Ghani without a military option. Ongoing negotiations in Qatar, the site of a Taliban office, also have failed to stop the insurgents' advance.

Earlier in the day, militants posted photos online showing them in the governor's office in Jalalabad, the capital of Nangarhar province.

Abrarullah Murad, a lawmaker from the province told The Associated Press that the insurgents seized the city after elders negotiated the fall of the government there. Murad said there was no fighting as the city surrendered.

The militants also took Maidan Shar, the capital of Maidan Wardak, on Sunday, Afghan lawmaker Hamida Akbari and the Taliban said. Another provincial capital in Khost also fell to the insurgents, said a provincial council member who spoke on condition of anonymity for fear of reprisals. Afghan officials said the capitals of Kapisa and Parwan provinces also fell.

The militants also took the land border at Torkham, the last not in their control, on Sunday. Pakistan's Interior Minister Sheikh Rashid Ahmed told local broadcaster Geo TV that Pakistan halted cross-border traffic there after the militants seized it.

Later, Afghan forces at Bagram air base, home to a prison housing 5,000 inmates, surrendered to the Taliban, according to Bagram district chief Darwaish Raufi. The prison at the former U.S. base held both Taliban and Islamic State group fighters.