Faced with unexpectedly rapid military gains by the Taliban, Britain and the US will deploy troops in Afghanistan to help their citizens get out of the country as the security situation worsens.

In response to the militants’ swift and violent advances that are further loosening the Afghan government’s hold on the country, the Pentagon said it would temporarily send about 3000 extra troops within 48 hours to help move embassy staff.

Britain said it would deploy about 600 troops to help its nationals and local translators get out.

The reinforcements will fly in just weeks before the departure of the last of the US-led international force that has had a core role in maintaining security in the country.

News of the drawdown underscored Washington’s rapidly deteriorating hopes that diplomacy will halt the Taliban’s advance and keep the capital in the Afghan government’s hands.

“We’ve been evaluating the security situation every day to determine how best to keep those serving at the embassy safe,” State Department spokesman Ned Price said on Thursday.

“We expect to draw down to a core diplomatic presence in Afghanistan in the coming weeks,” he said, adding the embassy was not closed.

President Joe Biden ordered the drawdown during a meeting on Thursday (local time) with top security advisers and accepted their recommendation to do so, a source said.

A decision to stay in the country might have required the commitment of many more US troops there to fight a civil war, the source said, as the United States looks to end its 20-year presence prompted by the September 11, 2001, attacks.

Still, the drawdown decision cast new doubt on Washington’s strategy to influence the country’s peace process by maintaining aid and diplomatic personnel even after the troop withdrawal.

Administration officials did not adjust that timetable even as Mr Biden ordered additional troops to Afghanistan to help secure the exit of civilian personnel. The first deployment to the airport in Kabul was expected within 24 to 48 hours, said Pentagon spokesman John Kirby.

In Britain, Defence Secretary Ben Wallace said on Thursday hundreds of military personnel would help British citizens and local translators leave.

The British embassy in Kabul will be moved to a more secure location and will remain manned by only a core staff. The British ambassador, Laurie Bristow, will be among those staying in Kabul.

“I have authorised the deployment of additional military personnel to support the diplomatic presence in Kabul, assist British nationals to leave the country and support the relocation of former Afghan staff who risked their lives serving alongside us,” Mr Wallace said in a statement.

Last week, Britain advised all its citizens in Afghanistan to leave.

The several thousand being helped out of the country include Afghan interpreters and other local personnel eligible for relocation to Britain as well as others who hold British passports.

-with DPA