NATO heads of state and government kicked off their summit meeting on Tuesday night with a working dinner.

In the dinner and the following day, the leaders from 26 member countries will discuss, among other things, the NATO-led peace-keeping mission in Afghanistan and NATO's role in the 21st century.

Afghanistan is expected to dominate the talks as the credibility of the alliance is put to test by worsening security situation on the ground and the lack of flexibility on the side of NATO troops.

The NATO-led International Security Assistance Force (ISAF) in Afghanistan is facing unprecedented challenges in the country after it took over the control of the whole country in October.

In addition to new responsibilities, the increase of suicide attacks on ISAF since the end of last year has forced NATO countries to bring in an increasingly larger number of body bags.

The worsening security situation, especially in the south of the country, is deterring NATO member nations from contributing more troops needed to get the job done.

NATO Secretary General Jaap de Hoop Scheffer has said 2,500 extra troops plus equipment are needed to suppress the resurgence of the Taliban, which were overthrown in the 2001 war in Afghanistan.

NATO's 26 member states and 11 non-alliance partners have deployed some 32,000 troops in Afghanistan, including 12,000 American soldiers who were put under NATO command in October 2006.

U.S. President George W. Bush indicated earlier Tuesday that he would ask NATO allies to commit more troops to Afghanistan and seek confirmation from leaders that restrictions on the deployment area, operation and engagement with enemy, would be removed.

"For NATO to succeed, its commanders on the ground must have the resources and flexibility they need to do their jobs," he told participants of the Young Leaders' Forum and a think tank conference.

"This alliance was founded on a clear principle, an attack on one is an attack on all. That principle holds true whether the attack is on our home soil or on our forces deployed on our NATO mission abroad."

Discussions over NATO's future strategy will also take up a big chunk of the leaders' time.

A central issue would be Washington's proposal to launch a "global partnership" with countries that are out of the Euroatlantic area.

The proposal is causing concern among European allies that such a partnership would weaken the alliance's nature of collective defense for Europe and North America.

Europe also fears that its influence in the alliance might be compromised by the presence of the new partners.

The United States is advocating the idea of forging closer ties with Asia-Pacific countries such as Australia, New Zealand, South Korea and Japan.

The leaders will also discuss the alliance's enlargement. They are expected to send a message of encouragement, but no formal invitations will be issued at the summit.

Albania, Croatia and Macedonia are recognized as formal aspirant countries. They are participating in NATO's membership action plan, the last stage before formal invitations to join the alliance.

Georgia also has intentions to join, but are in an earlier stage of the process.

Ukraine's pro-West leaders, who gripped power in the "Orange Revolution," were eager to join the alliance. Momentum was lost, however, after pro-Russia Viktor Yanukovych became prime minister this year.

Editor: Donald