A top Nato official has urged member states to send more troops to Afghanistan, amid intense clashes with Taleban rebels in the south.
There are 37 nations with troops under Isaf command
Military Committee Chairman Gen Ray Henault told defence chiefs in Warsaw that while Nato had 85% of its required force, casualties were mounting.
Member states should provide all of what they had signed up to, he said.
Meanwhile, the Nato-led forces in Afghanistan said they had killed 40 more Taleban in an ongoing offensive.
The latest clashes occurred in Kandahar province, bringing to about 300 the number of insurgents killed since the operation began a week ago, Nato says.
Recent fighting has focused on Panjwayi district, where hundreds of Taleban fighters have threatened to attack nearby Kandahar city.
Nato says more than 40 Taleban were killed by air strikes and artillery barrages overnight. One Nato soldier also died in combat.
Reporters have been unable to visit the scene to verify casualty figures.
A Nato spokesman said a bomb-making factory had been found in the area, and that alliance forces had re-opened the main highway out of Kandahar to civilian traffic.
Fight gets tougher
The military chiefs are calling for about 2,500 extra troops to be committed.
BBC defence correspondent Paul Wood says this is far more than Nato officials were suggesting only a few days ago - and an indication of how much tougher the fight with the Taleban has become.
A number of Nato soldiers, most of them British or Canadian, have been killed in recent weeks.
Gen Henault urged member states to send "all the people and the capability" that had been signed up to.
"We are currently at about 85% of the requirements and want the remainder," he was quoted as saying by AFP news agency.
There are more than 20,000 US troops in Afghanistan at the moment, but only around 2,000 of them currently under Nato command.
When Isaf takes control of the east as well, in the comings weeks, a large part of the US forces are due to transfer to Nato control.
No further pledges of troops have so far been made at the meeting.
Officials from Turkey, Germany and Italy have expressed reluctance to move their troops from reconstruction work in safer parts of Afghanistan to the troubled south, our correspondent adds.
The aim of the Medusa offensive - which began on 2 September - is to drive the insurgents from their strongholds in Kandahar province.
It is the biggest operation in the area since the Nato-led International Security Assistance Force (Isaf) took over southern Afghanistan from a US-led coalition at the end of July.
But violence spread north, as a suicide bomber rammed his car into a US Humvee vehicle in the capital, Kabul, on Friday killing at least 16 people including two US soldiers.
About 30 people were wounded in the blast, which occurred near the US embassy.
A man claiming to be a spokesman for the Taleban told an Afghan news agency that the rebel group was behind the attack.
There have been a series of suicide bombings across Afghanistan, but such a large explosion in the centre of Kabul was unusual.
Security in the capital was boosted on Saturday, as Afghans prepared to mark the fifth anniversary of the assassination of Ahmad Shah Masood - the resistance leader under the Taleban regime.
He died in a suicide bombing in northern Afghanistan two days before the attacks on the US in September 2001.
Friday's car bomb attack took place near Masood Square - named after him.
Afghan army soldiers have set up checkpoints on roads leading into Kabul and have been searching cars.
The Taleban ruled Afghanistan until late 2001 when they were toppled by US-led forces in the wake of the 11 September attacks on New York and Washington.