NATO said Wednesday it will continue to help Ukraine, which has close ties with the military alliance, to push ahead with democratic reforms.

"Ukraine is a close and long-standing partner to NATO. And NATO is a sincere friend of Ukraine," alliance head Anders Fogh Rasmussen said.

"We stand ready to continue assisting Ukraine in its democratic reforms," he said as he went into a regular NATO defence ministers meeting.

Rasmussen said recent developments in Ukraine, once a Moscow satellite, will be discussed at the two-day meeting at NATO HQ in Brussels.

Asked if he had been in contact with Russia following the ouster of the pro-Russian president Viktor Yanukovych, Rasmussen did not reply directly.

"Let me stress that it’s for the Ukrainian people to determine what should be the future of their country," he said.

"We take it for granted that all nations respect the sovereignty and independence and territorial integrity of Ukraine."

"This is a message that we have also conveyed to whom it may concern," he said, without naming Russia.

Yanukovych and his allies are widely believed to have since gone into hiding in the Russian-speaking southern peninsula of Crimea, that is now threatening to secede from Ukraine.

Besides deep political and economic ties, Russia uses Crimea as the main base for its Black Sea fleet and there has been some speculation Moscow could intervene directly to secure the base in the event the country breaks apart.

In 1997, NATO set up a joint commission with Ukraine to oversee relations and in 2008 agreed that Kiev could be considered for membership of the Cold War era alliance.