NATO has officially welcomed seven new Central and Eastern European members to the alliance at a ceremony at its Brussels headquarters. NATO's biggest-ever expansion is designed to end Europe's east-west divide and guarantee stability and democracy in areas that were once under the sway of the Soviet Union.

One by one, the flags of Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia and Slovenia were hoisted alongside those of NATO's older members as a military band played their national anthems.

Bulgarian Foreign Minister Solomon Passy fought back tears as his country's flag was raised next to those of Belgium and Canada. His colleagues beamed with pride as their banners were hoisted up their respective flagpoles.

NATO Secretary-General Jaap de Hoop Scheffer called it a day of joy and said the new members - all former communist states - had to wait a long time to join the ranks of free nations.

Russia is not happy about NATO's expansion into the Baltic states and has warned that any troop movements by the alliance there would harm NATO-Russia relations. But Secretary-General de Hoop Scheffer downplayed fears of any new tensions with Moscow and welcomed the decision by Russia's new foreign minister, Sergei Lavrov, to join his NATO colleagues at talks in Brussels.

"We need a constructive partnership," he said. "I think it's in the interest of NATO, and it's in the interest of Russia as well to have this good partnership where we discuss all forms of practical cooperation. And I think the NATO-Russia Council has done very well over the past years. We discuss subjects on which we agree. But we also discuss the more difficult subjects on which we not immediately might agree. But this is what the NATO-Russia Council is for.

The NATO foreign ministers are discussing how they can turn their pledges to expand security in Afghanistan into concrete commitments of men and materiel. The alliance has been criticized by non-governmental organizations working in Afghanistan for planning to set up provincial reconstruction teams in safe areas of the country and for failing to deal with a resurgent drug trade, entrenched warlords and endemic violence there.

Although no decisions are expected at Friday's meeting on whether NATO should play a bigger role in Iraq, as the United States wants it to do, Romanian Foreign Minister Mircea Geoana voiced strong support for the alliance's involvement there.

"All of us, the countries that suffered under communist dictatorship, they not only have a strategic necessity to stabilize Iraq but they also have a moral obligation to assist this nation that has suffered a similar or even worse dictatorship than the one we had under Ceaucescu," said Mircea Geoana.

Also on the agenda is a discussion of NATO's efforts to stabilize peace in Kosovo following the recent outbreak there of ethnic violence between Serbs and Albanians. And Mr. de Hoop Scheffer vowed that NATO troops would continue to search for Bosnian Serb war crimes fugitive Radovan Karadzic despite a failed raid Thursday that left a Serb Orthodox priest and his son in a coma.

The secretary-general repeated NATO's mantra that war criminals can run but they cannot hide.

I would, of course, have liked and preferred this operation to be a success," he said. "But everybody is doing everything he or she can to get them because I think it's important for the region that they would go where they should be, which is to The Hague, to the International Tribunal."

NATO ministers are also expected to flesh out plans to help Mediterranean and North African nations to boost their counterterrorism efforts and reform their military forces.