The Taliban has declared the war in Afghanistan is over after insurgents took control of the presidential palace in Kabul as US-led forces departed and Western nations scrambled to evacuate their citizens.

President Ashraf Ghani fled the country on Sunday as the Islamist militants entered the city, saying he wanted to avoid bloodshed, while hundreds of Afghans desperate to leave flooded Kabul airport.

“Today is a great day for the Afghan people and the mujahideen. They have witnessed the fruits of their efforts and their sacrifices for 20 years,” Mohammad Naeem, the spokesman for the Taliban’s political office, told Al Jazeera TV.

“Thanks to God, the war is over in the country.”

It took the Taliban just over a week to seize control of the country after lightning sweep that ended in Kabul as Afghan forces, trained for years and equipped by the US and others at a cost of billions of dollars, melted away.

Al Jazeera broadcast footage of what it said were Taliban commanders in the presidential palace with dozens of armed fighters.

Mr Naeem said the form of the new regime in Afghanistan would be made clear soon, adding the Taliban did not want to live in isolation and calling for peaceful international relations.

“We have reached what we were seeking, which is the freedom of our country and the independence of our people,” he said.

“We will not allow anyone to use our lands to target anyone, and we do not want to harm others.”

A US State Department spokesperson said early on Monday (local time) that all embassy personnel, including ambassador Ross Wilson, had been transferred to Kabul airport to await evacuation and the American flag had been lowered and removed from the embassy compound.

Hundreds of Afghans invaded the airport’s runways in the dark, pulling luggage and jostling for a place on one of the last commercial flights to leave the country before US forces took over air traffic control on Sunday.

More than 60 western countries, including the US, Britain, France and Japan, issued a joint statement saying all Afghans and international citizens who wanted to leave the country must be allowed to depart.

In a Facebook post, Mr Ghani said he had left the country to avoid clashes with the Taliban that would endanger millions of residents of Kabul.

In Washington, opponents of President Joe Biden’s decision to end America’s longest war, launched after the September 11, 2001, attacks, said the chaos was caused by a failure of leadership.

Many Afghans fear the Taliban will return to past harsh practices in their imposition of sharia, or Islamic religious law. During their 1996-2001 rule, women could not work and punishments such as stoning, whipping and hanging were administered.

The militants sought to project a more moderate face, promising to respect women’s rights and protect both foreigners and Afghans.

“We are ready to have a dialogue with all Afghan figures and will guarantee them the necessary protection,” Mr Naeem told Al Jazeera Mubasher TV.

United Nations Secretary-General Antonio Guterres urged the Taliban and all other parties to exercise the utmost restraint, and expressed particular concern about the future of women and girls in Afghanistan.

The Pentagon authorised another 1000 troops to help evacuate US citizens and Afghans who worked for them, a US official said.

European nations, including France, Germany and the Netherlands, also said they were working to get citizens as well as some Afghan employees out of the country.

In Canberra, Prime Minister Scott Morrison refused to comment on whether the Taliban’s lightning advance through Afghanistan had upended rescue plans.

“I can’t really talk about operations, but what I can tell you is since April of this year, we’ve obviously been anticipating this situation,” he told the Seven Network on Monday.

Since April, Australia has evacuated 430 Afghan employees, and their families, who assisted with the war effort over the past two decades.

Earlier, US Secretary of State Antony Blinken was asked if images of helicopters ferrying personnel were evocative of the US’ departure from Vietnam in 1975.

“Let’s take a step back. This is manifestly not Saigon,” he told the US’s ABC News.

Mr Biden has faced rising domestic criticism after sticking to a plan, initiated by his Republican predecessor, Donald Trump, to end the US military mission in Afghanistan by August 31.

On Sunday, Senate Republican leader Mitch McConnell blamed Biden for what he called a “shameful failure of American leadership”.

“Terrorists and major competitors like China are watching the embarrassment of a superpower laid low,” Senator McConnell said.

-with AAP