The 26-nation body has approved plans to increase troops to about 17,000 from 9,000 and expand into the insurgent-troubled south by late July, taking the alliance into what could be its toughest ground combat since its creation in 1949.
''We will succeed because it's important for the Afghan people and we think important for the world,'' said Dutch Defence Minister Henk Kamp, arriving for a meeting of alliance defence ministers at NATO headquarters in Brussels.
The Netherlands is among the countries deploying troops in the south as part of NATO's expansion. Kamp said they would be deployed over the next two months.
Asked about dangers to the force posed by the Taliban and their Islamist militant allies, he replied: ''We need to be concerned to do our job properly.'' ''We will see what's going on there and based on our experiences see what we have to do.'' Guerrillas have stepped up attacks in what NATO sees as an attempt to unnerve it. About 400 people were killed in May alone in the bloodiest phase of the Taliban insurgency since U.S.-backed forces overthrew the Islamist government in 2001.
''We hope that with the reconstruction work going on, and with the efforts of the Afghan government on counter-narcotics we will make progress,'' said German Defence Minister Franz Josef Jung, acknowledging that the rise in violence was a concern.
Britain and Canada will join the Netherlands in leading the deployment in the south, which includes Afghanistan's main opium-growing region and most dangerous territories.
NATO officials say the recent violence has not prompted it to review existing plans to replace an estimated 3,000 US troops in the south with 6,000 alliance-led peacekeepers under order to deal toughly with threats.
Critics of the mission say troop levels are too low to bring genuine security and question whether the European public has been adequately prepared for the real risk of casualties.
NATO is already present in the capital Kabul, the west and north of Afghanistan.
The ministers will also review NATO efforts to reform itself from Cold War giant to a nimbler security organisation able to respond to crises in trouble spots at short notice.
European member states will be pressed to set aside more troops for a NATO rapid-reaction force due to be fully operational from October with a total strength of 25,000.
The United States in recent weeks pledged to reserve almost 6,000 troops for the so-called NATO Response Force, but diplomats say the head count is still short.
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