Russia should not intervene in Crimea after gunmen seized the Ukrainian region’s parliament, the secretary-general of NATO said on Thursday.

Anders Fogh Rasmussen said such action by Moscow would only make the situation worse.

“I am extremely concerned about the most recent developments in Crimea,” he told NATO defence ministers.

“I urge Russia not to take any action that could escalate tension or create misunderstanding.”

Those calls have been echoed by Ukraine’s interim president, Olexander Turchynov.

Ukraine envoy to NATO Ihor Dolhov told euronews: “It was very important for us to hear that NATO member states have sent a clear signal that NATO supports Ukraine’s sovereignty, territorial integrity and the inviolability of its borders.”

US Air Force General Philip Breedlove, NATO’s most senior commander, was quoted by Reuters as saying that neither the alliance nor the US have made any contingency plans to intervene if Russian troops do attack.

“No, no, we have taken no actions to this moment. We are doing what everyone else is doing which is monitoring. We are trying to get to a full understanding of exactly what has transpired,” Breedlove was quoted as saying by the news agency.