Afghanistan is poised for an announcement that it is now the Islamic Emirate of Afghanistan, under Sharia law, after the Taliban swept to power.

It follows a spokesman for the group telling AP it is holding talks aimed at forming an "open, inclusive Islamic government" and the deputy leader of the group releasing a video saying it plans to "give serenity to the whole nation".

Taliban officials have declared the war is over and it is in charge of 90% of government buildings, amid allegations of revenge killings and brutal tactics.

Afghanistan live updates: All the latest as the Taliban establish new government

But, amid the statements, chaotic scenes are unfolding at Kabul's international airport with thousands of people trying to get past a cordon to aircraft that are evacuating diplomatic staff.

A spokesperson for the German government said no flights are leaving Kabul airport at the moment because desperate people trying to flee the country are blocking the tarmac - something later confirmed to Reuters by an unnamed US defence official.

The German government had said it wanted to evacuate 10,000 staff, civilians and Afghans it has worked with, but later changed that pledge to as many as possible, with no concrete figure.

Footage has emerged, which Sky News has not been able to verify, of an Apache helicopter being used to clear a runway as a C-17 military transport plane comes in to land.

Five people are reported to have been killed as US troops guarded the evacuation of embassy staff but it was not immediately clear how they died.

A US official said soldiers had fired in the air to deter people trying to force their way onto a military flight that was set to take US diplomats and embassy staff out of the fallen city.

An official described the crowd trying to get onto the tarmac at the airport as "out of control" and other images showed people climbing on to an airbridge that allows people to walk onto an aircraft from a terminal and onto the undercarriage housing of a military plane taxiing along the runway.

British and US forces are on the ground in the military side of the airport and The US said it would focus intensively on securing Kabul airport with additional US forces being flown in to help achieve the aim.

Afghanistan's aviation authorities said the "civilian side" of the airport had been "closed until further notice" and there are reports that the US has taken over air traffic control to ensure safety in the region, with many carriers saying they would be avoiding airspace above the country.

Sky's Stuart Ramsay, who is near the airport, has said he has heard the sound of gunfire outside and the constant noise of helicopter gunships flying overhead, but says on the ground the people are already dressing differently, in readiness for a Taliban takeover.

It comes as many of the countries which have been involved in the efforts to rebuild the country amid two decades of war with the Taliban have pulled out their diplomatic staff and are attempting to evacuate their civilians and Afghans who had helped them.

Among the countries planning to pull out staff was Russia, which launched an invasion in 1979 and fought mujahideen including members of the Taliban during a 10-year war. It came as the Taliban deployed guards to the Russian embassy.

The first group of evacuated Britons and embassy staff arrived at RAF Brize Norton last night, the Ministry of Defence confirmed.

There were reported to be 4,000 Britons in Afghanistan and the UK has said it plans to ramp up efforts to evacuate up to 1,500 people from Afghanistan a day.

The Taliban, who ruled from 1996 to 2001 until a US-led invasion reduced them to conducting a guerrilla war, have routed the US-backed government's forces following a US decision to pull out its troops.

President Ashraf Ghani fled the country on Sunday as the Islamists began to enter Kabul virtually unopposed - despite ongoing but short-lived resistance elsewhere - saying he wanted to avoid bloodshed.

But Russia's embassy in Kabul said the next day that he had fled with four cars and a helicopter full of cash, and had to leave some money behind as it would not all fit in.

Taliban says its 'type of rule' will become clear soon after President Ashraf Ghani flees

Taliban spokesperson Suhail Shaheen said in a message on Twitter its fighters were under strict orders not to harm anyone and on Monday it put out videos showing quiet city streets in Kabul as fighters manned major intersections.

A Taliban official said its fighters in Kabul had started collecting weapons from civilians on Monday because people no longer need them for personal protection.

The Russia-led security bloc CTSO, which includes central Asian states such as Kazakhstan, Kyrgyzstan and Tajikistan, but excludes Uzbekistan, said it was deeply concerned by the Taliban taking control in Afghanistan will have a significant impact on the situation in Central Asia.

Russia is said to be talking to the US about the deteriorating situation.

President Joe Biden, whose order pulling out US troops from the country preceded the Taliban surge, was seen at his Camp David retreat on Sunday, alone in a conference room meeting virtually with military, diplomatic and intelligence experts.

US officials are said to be stunned by how quickly the Taliban have overcome Afghan forces, despite the billions spent on military hardware and training to equip them for the fight.

While Mr Biden has yet to speak publicly, US National Security Adviser Jake Sullivan said the Afghan military was to blame. "We could not give them the will and ultimately they decided that they would not fight for Kabul," he said.

Not all foreigners were pulling out. Doctors Without Borders (MSF) said its operations across Afghanistan have not been affected and the United Nation's Office for the Coordination of Humanitarian Aid (OCHA) said it and its partners "are staying and delivering to people in need".

China says its embassy remains open in Kabul and said it was willing to help reconstruct the country, and while not commenting on whether Beijing would recognize the Taliban as the new government, said it would respect the choice of the Afghan people.

A meeting of the 15-member UN Security Council is due to take place at 3pm UK time, after a request from Estonia and Norway, both of which were part of the ISAF coalition which battled the Taliban during the last two decades.

Iranian President Ebrahim Raisi said on Monday the United States' "military failure" presented an opportunity to establish lasting peace in Afghanistan.