Theresa May has hosted Nato's secretary general for a meeting at Downing Street amid speculation that she may commit to sending more British troops to Afghanistan.
It is understood that Nato have asked Mrs May to commit extra forces to help bolster the struggling Afghan National Army.
She is said to be considering the request with a mind to sending a small number of extra forces - likely to be no more than 150.
Nato secretary general Jens Stoltenberg confirmed that international group wanted "a few thousand" additional troops for Afghanistan which would come from all allied forces including Britain.
Mr Stoltenberg added the UK had "led by example" within the group, including by keeping forces in Afghanistan for many years and by meeting targets for member states to spend 2% of GDP on defence.
"Also in the cause of fighting terrorism, I very much appreciate the contribution from the United Kingdom. You have been in Afghanistan for many many years, together with all the Nato allies," he added.
He confirmed that troop levels in Afghanistan would be discussed at a Brussels summit on May 25.
Meanwhile Mrs May stressed that she would be pushing for the Brussels discussions to ensure other nations "play their role", including by meeting the target of spending 2% of national income on defence.
Around 500 British troops are already in Afghanistan in training and mentoring roles asthe local security forces continue to battle the Taliban.
The issue risks becoming caught up in the heat of the General Election campaign after Labour leader Jeremy Corbyn suggested he would be prepared to turn down any Nato request for reinforcements.
The Labour leader said "at the end of the day wars are not solved by the presence of foreign troops" as he called for a political solution to the violence in the war-torn nation, while vowing to "look at" any request.
A Ministry of Defence spokesman said: "The UK keeps its contribution in Afghanistan under regular review to ensure it remains suited for the needs of the mission."