David Miliband has refused to rule out further increases to Britain's commitment of troops in Afghanistan. On a surprise visit to Kabul and Helmand today, he declined to scotch reports that up to 2,000 British soldiers will be despatched to Afghanistan next year, as Britain draws down its commitments in Iraq.

Asked whether Britain would answer calls for more troops from the incoming Obama Administration, Mr Miliband replied: "We'll say that our commitment is already 8,100 troops, and any question of more troops depends on what they would do and whether they are part of a genuinely comprehensive strategy.

"I think the most important thing to say is that the biggest source of new troops for the medium term in Afghanistan is the Afghan National Army, which I will be visiting later today in Helmand.

"If, in the interim, they need more foreign troops, that's something the American government have made a commitment to, but we've been absolutely clear that a military strategy will only work if it's alongside an economic and political strategy as well. And so we do look forward to working with the Obama administration on this issue. It is their top priority, and it's a very, very high priority of ours as well."

The US military is expected to send between 15,000 to 20,000 extra troops next year in an attempt to halt the relentless decline in the security situation in Afghanistan. It is also suggested that Britain has already secretly made a commitment to send 2,000 more to Helmand.

Mr Miliband called the figure "speculation" and added: "I haven't seen any papers that come to me saying we need 2,000 more troops. The Ministry of Defence organises these assessments of what's needed in a very coherent, very systematic way, and we're not going to do it on the basis of plucking numbers out of the air."

However, in an interview with The Times in September, the outgoing of UK forces in Helmand, Brigadier Mark Carleton-Smith, acknowledged that more troops were needed in the province to create secure conditions for Afghan security forces to begin to takeover in between three and five year.

"I think we will be at this level and potentially growing incrementally over the next three to five years," he said. "We must grow in order to expand the capacity of the Afghan National Army. We need more mentors to grow them harder, faster, quicker. They will not necessarily be British troops. We will look to the US, possibly for several brigades."

Brigadier Carleton-Smith said: "Afghan military capacity will mature quite quickly, but Afghan political maturity will be measured in decades and generations."

The current British deployment of 8,100 troops includes 5,500 fighting soldiers, with the rest supporting a lengthy logistical tail in the relentlessly hostile environmental conditions that prevail in Helmand.

According to the website icasualties.org, which collates all reported casualties in Afghanistan and Iraq, this year has seen 262 deaths for Western forces in Afghanistan, compared to 232 for the whole of last year.

Five British soldiers have been killed so far this month, four of them in roadside bomb and mine strikes - the latest a Royal Marine killed near Kajaki in the north of the province yesterday.

US officials have privately expressed frustration with the lack of essential equipment, particularly helicopters, suffered by British and other NATO nations with forces in the south.

In a succession of inquests into the deaths of British soldiers, coroners have criticised equipment shortages that left troops vulnerable to roadside bombs and unable to communicate; in some cases forcing British soldiers to attract the attention of other units by firing shots in the air.

A recent BBC opinion poll claimed that 70% of the British public support pulling out UK forces.

Times Recommends

• It’s only Brits who don’t appreciate me, says Blair
• Party’s over for Greek graspers
• White House tightens security for Xmas marathon