Nato expansion unlikely before late 2015

He added that the two sides will “intensify” co-operation in the meantime, with Nato officials saying Montenegro still has homework on technical military standards.

Two other countries - Bosnia and Macedonia - have membership action plans.

Georgia has asked to join. Opinion surveys in Ukraine after Russia invaded the country say most people also want to be in the alliance.

Rasmussen noted that Georgia’s next step is to become part of an “enhanced co-operation group”, together with Australia, Jordan, Moldova, and Sweden.

He did not mention Ukraine.

But he added, alluding to Russia’s opposition to Nato expansion, that: “Nato’s door remains open. Each country will continue to be judged on its merits and no third party has a veto over Nato enlargement”.

Ukraine is planning to introduce a bill to scrap its non-aligned status so that it can apply one day.

Ukrainian president Petro Poroshenko, speaking in Wales on Wednesday, indicated that he might hold a referendum on the question in the coming years.

“When the country will be adequately prepared for the [technical] criteria of membership, the Ukrainian people will decide”, he said.

But German chancellor Angela Merkel told German press the same evening that Ukrainian accession is not on Nato’s agenda at this time.

On Bosnia, a Nato official said it is stuck in limbo, due, in part, to disagreements between ethnic Serbs and Bosniaks on which bits of the federation should host which military bases.

He added that Greece-Macedonia talks “have not gone well” on the name dispute, which has seen Greece veto Macedonia’s Nato entry because Macedonia uses the same name as a bordering Greek province.

Rasmussen’s comments on Russia’s non-veto come despite the risk that pro-Russia forces will occupy east and south Ukraine in a frozen conflict designed to stop it from joining Western blocs.

The situation already exists in Georgia and Moldova, where Russian soldiers protect three breakaway republics.

The Nato official added that a border dispute does not categorically rule out Nato entry, however.

“It’s not a show-stopper”, he said, noting that Norway joined the alliance despite having a maritime boundary dispute with Russia at the time.

Two other Nordic nations - Finland and Sweden - at the Nato summit signed a “host nation status” agreement which allows Nato troops to deploy on their territory in future.

Neither has joined Nato because Finland is wary of antagonising Russia, but both have worked on Nato “inter-operability” for several years.

Asked by EUobserver if Rasmussen’s mention of late-2015 means no new members until that time, the Nato official said “unless of course Finland or Sweden opt to join … if they do, they would walk in within a week”.