NATO foreign ministers meeting in Oslo Thursday debated providing security guarantees to Ukraine after its war with Russia ends, as the alliance looks to bridge divisions over Kyiv's push to join the bloc.

Russia's invasion of Ukraine in February last year has galvanized the Western military alliance set up almost 75 years ago to face off against the Soviet Union.

But with just over five weeks to a summit of NATO leaders in Lithuania's capital Vilnius there are splits on key issues.