Kabul, Aug 16 (IANS): A Taliban commander claimed that he spent eight years in the Guantanamo Bay prison in Cuba in a triumphant speech from inside the Presidential Palace in Kabul as the militants declared an Islamic state of Afghanistan after the country's President joined thousands of citizens in a mass exodus, the Daily Mail reported on Monday.

Taliban fighters marched into the ancient palace on Sunday and demanded a "peaceful transfer of power" as the capital city descended into chaos, with US helicopters evacuating diplomats from the embassy in scenes echoing the 1975 Fall of Saigon which followed the Vietnam War.

There were chaotic scenes at Kabul airport where thousands of desperate Afghans are gathering in an attempt to flee the country.

Fighting and stampedes broke out between passengers before commercial flights were stopped and only military planes departed the terminals which are now guarded by US troops.

Foreigners in Kabul were told to either leave or register their presence with Taliban administrators, while RAF planes were scrambled to evacuate 6,000 British diplomats, citizens and Afghan translators, and the British Ambassador was moved to a safe place.

Prime Minister Boris Johnson said the US decision to withdraw from Afghanistan had "accelerated" the current crisis and announced his government's priority is to get UK nationals out "as fast as we can".

The British ambassador is still at the airport processing visas for Afghans who have helped the UK.