LONDON -- British Secretary of Defense Ben Wallace on Friday said the U.S. decision to pull its troops out of Afghanistan was a "mistake," which has handed the Taliban "momentum" in the country.

Speaking to Sky News, Wallace said the withdrawal agreement negotiated in Doha, Qatar, by the Trump administration was a "rotten deal".

"At the time of the Trump deal with, obviously the Taliban, I felt that was a mistake to have done it that way. We will all, in the international community probably pay the consequences of that," Wallace said.

"I've been pretty blunt about it publicly and that's quite a rare thing when it comes to United States decisions, but strategically it causes a lot of problems and as an international community, it's very difficult for what we're seeing today," he said.

"Of course I am worried, it is why I said I felt this was not the right time or decision to make because, of course, al-Qaida will probably come back, certainly would like that type of breeding ground," he added.

Talking about the withdrawal of British troops from the country, Wallace said Britain had no choice but to pull its forces out, because the international community had to act together.

"When the United States as the framework nation took that decision, the way we were all configured meant that we had to leave," he said.

The defense secretary also confirmed that Britain will deploy 600 troops to Afghanistan to help British nationals and interpreters leave the country. The United States said on Thursday that it will deploy thousands of troops to Kabul airport to support embassy staff drawdown.

The situation in the war-torn country has been worsening since the withdrawal of U.S.-led troops starting on May 1.

Many Afghan cities and about half of the country's 34 provinces in recent weeks have seen heavy battles and street fighting between Afghan forces and Taliban militants. The Taliban claims to have taken control of at least nine provincial capitals so far.

U.S. President Joe Biden ordered the U.S. military to end its mission in Afghanistan by the end of this month.

Earlier this month, Afghan President Mohammad Ashraf Ghani blamed the speedy withdrawal of U.S.-led troops for the worsening violence in his country. Pakistani Foreign Minister Shah Mahmood Qureshi on Monday also warned that the irresponsible withdrawal of U.S. and NATO forces from Afghanistan may benefit the militants and lead to unrest in the country.