LONDON: Britain plans to withdraw thousands of troops from Afghanistan next year, Defence Secretary Philip Hammond said on Sunday, as pressure mounts to end British involvement in the costly and unpopular war.

More than 430 British troops have been killed in Afghanistan since the US-led intervention in 2001, yet stability remains elusive and violence high, while relations between Western troops and Afghan forces and civilians are increasingly frayed.

Britain on Sunday said it had charged five soldiers with murder as part of an investigation into what it called an engagement with an insurgent in Afghanistan last year, and that a total of nine soldiers had been arrested in connection with the case.

Some 500 British troops are to be withdrawn from Afghanistan by the end of this year, leaving around 9,000 still there.

Asked about troop withdrawals next year, Hammond told the BBC: “I would expect it will be significant, which means thousands, not hundreds, but I would not expect it to be the majority.”

That would indicate a potential withdrawal of up to 4,500 personnel in 2013.

All British combat troops are due to leave Afghanistan by the end of 2014.

Britain’s defence budget, like that of other Nato members, is under pressure, forcing the defence ministry to slash spending and cut force numbers and equipment programmes.

The Treasury, struggling to revive a flagging economy, earlier this year said it would use money once earmarked for the military mission in Afghanistan to fund tax cuts.

German news magazine Der Spiegel said on Sunday that the German government had agreed to reduce the number of German troops stationed in Afghanistan to significantly below 4,000 ahead of the withdrawal of the Nato-led International Security Assistance Force (Isaf) by the end of 2014.

The magazine also said German Defence Minister Thomas de Maiziere and Foreign Minister Guido Westerwelle had agreed that the army's new mandate would be longer than the usual 12 months so that it extended beyond the Afghan presidential elections planned for the beginning of 2014.

A spokeswoman for the German defence ministry said neither numbers nor a timeframe had been determined and added that a decision on how many troops could be withdrawn would have to be made in agreement with Germany's allies.

Murder Charge

Media reports said the murder investigation was triggered by footage discovered on the laptop of a man who had been serving in Afghanistan of what appeared to be a wounded insurgent and of British soldiers discussing whether to administer first aid.

The ministry said it could neither confirm or deny the reports.

“The Royal Military Police (RMP) has arrested two further Royal Marines on suspicion of murder in relation to an incident alleged to have taken place in Afghanistan in 2011, taking the total number arrests to nine,” the ministry said.

“The RMP has referred the cases of the remaining five Royal Marines to the independent Service Prosecuting Authority ... these marines have now been charged with murder,” it added.

Relations between Western forces and Afghan civilians have been strained in the past year after U.S. soldiers burned copies of the Quran at a Nato base and a US soldier was accused of killing 16 civilians in a rampage in March.

A video surfaced in January depicting US Marines urinating on corpses.

Ties between Western troops and Afghan forces have also deteriorated after a series of “insider” attacks against Nato coalition troops by Afghan soldiers or by militants wearing Afghan military uniform.