NATO's military operation in Afghanistan will succeed, the alliance's chief said on Tuesday, urging member countries not to lose heart despite a strengthening Taliban insurgency and unexpectedly high casualties.
Speaking to a forum before a two-day summit, NATO Secretary-General Jaap de Hoop Scheffer insisted the alliance would prevail in its first mission outside Europe.
He also hoped that by 2008, Afghan forces could begin to take over security tasks.
"I would hope that by 2008, we'll have made considerable progress ... (with) effective and trusted Afghan security forces gradually taking control," he said.
Although De Hoop Scheffer predicted that by 2008, the North Atlantic Treaty Organisation also would be able to reduce its presence in Kosovo, where about 17,000 peacekeepers are deployed, he said he could not yet envisage drawing down in Afghanistan.
"Our exit strategy will depend on Afghanistan having its own security forces," he said, adding that NATO would launch a training program for the Afghan army.
"Afghanistan is 'mission possible,"' he said. "We need to be frank about the risks, but we also need to avoid overdramatising.
NATO has been in Afghanistan for three years -- time enough to know what it takes to succeed."
The United States President George W Bush, speaking in neighboring Estonia, urged NATO nations to provide the forces required by the alliance commanders in Afghanistan.
Making a stop on his way to the Latvia summit -- his first meeting with European allies since the Democratic triumph in the US midterm congressional elections -- Bush said the 26 NATO allies must be ready to face difficult challenges in Afghanistan.
The dangers to the NATO force were underscored by recent attacks that have shattered a period of relative calm.
Two Canadian soldiers were reported slain by a suicide car bomber on Monday.
A day earlier, a suicide bomber killed 15 Afghans in a restaurant. De Hoop Scheffer also called for sweeping reforms to transform NATO into "a major strategic tool for coping with 21st century challenges."
"There are still too many messages of the Cold War in the way the NATO is structured," he said.
"Partnerships with nations around the world ... hold much potential. The decisions I expect from our summit here should help us unlock this potential."
At its summit in the Latvian capital of Riga, NATO leaders also planned to explore the possibility of forging closer ties with their Pacific allies.
The alliance also was expected to reaffirm its "open-door policy," reiterating that Croatia, Macedonia and Albania can join when they fulfill all the requirements -- but will not give a precise entry date for any of those ex-communist candidates.
NATO's emerging new role as a guarantor of peace in global hotspots will be discussed at the summit of 26 presidents and prime ministers, the first such gathering on the territory of the former Soviet Union.
Latvia broke away from the Soviet sphere in 1991 and joined NATO in 2004.