LONDON - Britain will extend its military presence in Afghanistan by a year due to the ongoing security challenge faced by Afghan forces, Defence Secretary Michael Fallon said on Tuesday.

The Taliban has launched sustained attacks since the withdrawal of most foreign troops late last year, straining the limited resources of Afghan forces. Many districts across the country are now fully or partially under Taliban control.

Fallon said the Afghan National Defence and Security Forces (ANDSF) had been "tested" over the last year but were increasingly professional and competent.

"The UK Government recognised it would take time for the ANDSF to develop into a fully-fledged fighting force capable of providing complete security for the people of Afghanistan," Fallon said in a written statement to parliament.

"We have now concluded that we should maintain the scale of the UK's current military mission in the country in 2016, to help build a secure and stable Afghanistan. The scope and role of the UK mission are unchanged."

Britain had previously committed to keeping troops in Afghanistan until the end of this year. It has around 450 troops involved in training at the Afghan National Army Officer Academy, working with the Afghan security ministries, and supporting NATO operations in Kabul.

The decision follows an announcement by President Barack Obama earlier this month that the United States would slow the pace of troop withdrawal due to the "very fragile" security situation there.

British troops ended their combat operations in Afghanistan in October last year, 13 years after the U.S.-led invasion which launched a long and costly war against the Taliban.