Nato foreign ministers are meeting in the Lithuanian capital, Vilnius - the alliance's first major gathering in a former Soviet republic.
Nato was hoping to improve relations with Russia at the meeting
One of the dominant themes will be a possible further expansion of Nato to include Ukraine, which has entered an intensive dialogue with Nato.
Lithuania and six other ex-communist states joined Nato a year ago.
Russia remains concerned about Nato's growing influence in the former Soviet Union, correspondents say.
The BBC's Jonathan Beale in Vilnius says Nato hopes to have reassured Russia and improved relations with it by inviting it to this informal meeting of foreign ministers.
Ukraine, for its part, has yet to prove its long-term commitment to military and democratic reform, our correspondent says.
Nato ministers have pledged to help Ukraine with those reforms but have not committed to eventual membership.
Nato spokesman James Appathurai said the alliance would offer Ukraine a "form of enhanced dialogue, together with a package of practical and political elements".
Nato ministers are expected to discuss a range of issues including the Middle East peace process, the training of Iraq's security forces, and the situation in the Sudan's Darfur region.
All of the alliance's 26 members are now contributing to the training of Iraqi security forces - though some of that help is only financial.
The organisation is hoping to set up a new training facility outside Baghdad by the autumn.
On Wednesday, Nato foreign ministers held a discussion on the Middle East peace process.
Officials have said Nato members agree they must be ready to consider a role supporting the Middle East peace process if asked for, but say it is premature to discuss concrete options.
"Nato is not, I repeat, not, going to intervene," Nato chief Jaap de Hoop Scheffer told a news briefing.
He added that any Nato presence would have to be requested by both parties and have a UN mandate.