Nato backed a plan on Friday to take foreign troop numbers in Afghanistan to their highest level since the Taleban's overthrow sending the alliance on what is set to be the toughest ground mission in its 58-year history.
The Nato strategy nearly doubles its troop numbers to more than 16,000 from July to help the United States wind down its presence in the perilous south and gives peacekeepers greater scope to engage insurgents.
Speaking after a meeting of Nato foreign ministers in the Bulgarian capital Sofia, alliance Secretary-General Jaap de Hoop Scheffer said they had given a strong commitment to expansion of the International Security Assistance Force (ISAF).
They also agreed the troops would be able to employ "robust" rules of engagement, he said.
"Only a sustained and concerted effort will yield success," de Hoop Scheffer told the Sofia meeting, stressing Nato was determined to see its mission through despite a rise in violence directed at international troops.
The Nato expansion will take the numbers of foreign soldiers in Afghanistan to around 32,500 by July and August, the highest level since US-led forces overthrew the Taleban in late 2001.
About half the total will be with a separate US-led force hunting the Taleban and its allies since 2001.
Nato officials said there had been no consensus on when ISAF would take over responsibility from the US-led force in the east of the country, where Islamist insurgents are also active.