UK troops arrive in Kabul

UK troops have arrived in Kabul to aid British nationals and diplomats still in the country as the Taliban closes in on the Afghan capital.

UK troops arrive in Kabul
Members of the 16 Air Assault Brigade arrive in Kabul as part of a UK-force sent to assist with Operation PITTING to rescue British nationals in Afghanistan. (AP)

About 600 troops are expected to take part in Operation Pitting, to assist in the evacuation of UK nationals remaining in Afghanistan. 

Boris Johnson said it was his 'priority' to make sure British nationals were removed from Afghanistan amid the chaos.

Incumbent president Ashraf Ghani has reportedly left the country for Tajikistan, according to an interior ministry official.

The Taliban said Sunday that their militants have entered multiple districts in the Afghan capital Kabul, while sources said they had also taken over the presidential palace, hours after leader Ashraf Ghani fled the country.

"Military units of the Islamic Emirate of Afghanistan have entered Kabul city to ensure security," Taliban spokesman Zabihullah Mujahid tweeted, adding that "their advance is continuing normally".

Three senior Taliban sources also told AFP that "The mujahideen have entered the presidential palace and have taken control of it," adding that a meeting on security in the capital was taking place there.