Defense ministers from Central and Eastern Europe are celebrating the anniversaries of their countries' membership of NATO at a time when Russia's increased military activity has stoked concerns.

The nine ministers are meeting in Poland, the largest of the post-communist countries in the region.

Their nations joined the military alliance, which is based in Brussels, between 1999 and 2004, sealing their new links with the West and away from Russia.

Their membership also shifted the center of Europe's security eastwards, toward Russia, to the increasing annoyance of Moscow.

The two-day meeting that ends Friday is focusing on improving the alliance's combat readiness in the region.