The agreement, endorsed at an informal two-day meeting of alliance defense ministers, would see some 12,000 US troops come under NATO control within Afghanistan's International Security Assistance Force (ISAF) within weeks.
The decision came as Germany's parliament, the Bundestag, voted to extend the country's mission in Afghanistan by another year. The mandate allows up to 3000 Bundeswehr soldiers to be deployed as part of ISAF.
But German Defense Minster Franz-Josef Jung promised that the troops would not be deployed in the troubled south of the country -- although NATO allies are pressing Germany to lift this restriction.
Five years after ousting the Taliban regime in Afghanistan, US-troops and NATO peace-keepers are still not able to provide security for the entire country.
Since the beginning of the year, Taliban and terrorists have killed 100 foreign soldiers and about 2000 civilians. For some months now, new Taliban forces have been attacking NATO-forces, trying to set up reconstruction teams around Kandahar. In the East US-troops are trying to reclaim Taliban-infested territory.
The move would put ISAF in control of international operations across the country, boosting its numbers to more than 30,000 troops -- almost half of them US forces -- from some 37 nations.
It would also permit NATO's commanders to move US soldiers from the east down to the Taliban's southern heartland, where British, Dutch and Canadian troops have been locked in battle with Taliban-led fighters.
"Expect (the expansion) to happen very soon indeed," NATO Secretary General Jaap de Hoop Scheffer told reporters in Portoroz, Slovenia after the first day of talks.
"You have to deliver"
Both US Defense Secretary Donald Rumsfeld and Scheffer urged the NATO allies to do more, amid a general reluctance to supply around 2,000 reinforcements in the south in response to a demand earlier this month by supreme commander US General James Jones.
"If you are in an alliance based on solidarity, you have to deliver," Scheffer said.
Poland will speed up its deployment of around 1,000 personnel and is expected to provide many of the combat troops needed in the south. NATO sources said Romania, Canada, Denmark and the Czech Republic also made offers.
Hearts and minds
The Taliban, ousted by the US-led military coalition in late 2001 for harboring al Qaeda leader Osama bin Laden, has been backed by allies among drug runners and fighters loyal to local warlords.
As it seeks to reclaim Taliban-infested territory, ISAF also hopes to win hearts and minds by helping build new roads, bridges and schools, as well as provide jobs.
But development is lagging and NATO's most ambitious security enterprise faces failure if Afghans lose interest in democracy and turn once again to the fundamentalist militia.
Analysts have suggested that NATO'S worst nightmare might well come true, with Afghans losing interest in democracy and a state modeled after western values. If the NATO-led international security force does not succeed in providing more efficient security in Afghanistan, sources in the alliance say that people will start to support the Taliban again.
The major challenges include building an Afghan police force, fighting corruption and ending the opium trade.
"It is winnable but it requires a concerted effort," said NATO spokesman James Appathurai, and added: "the international donors, the United Nations, the European Union, the non-governmental organizations, they all have to step up their game, all of them."