Romania has given the green light to NATO to base fighters there as the crisis in neighbouring Ukraine deepens, its president said Wednesday.

"These planes will be part of the NATO integrated defence system alongside the Romanian air force," Traian Basescu said after a meeting of the country's defence council.

"As many as 200 pilots, mechanics and maintenance personnel will be stationed on Romanian territory," he said.

Basescu has urged Europe to take a stronger line with Russia over Ukraine, and called on NATO on Wednesday to reinforce its eastern flank in case the situation degenerated futher.

"The presence of the Russian fleet in the Black Sea worries us," he said.

Last week he called for the EU and NATO to supply weapons to Kiev to help the country fight pro-Russian insurgents in the east.

The decision comes as the alliance begins a major meeting in Newport, Wales, on Thursday dominated by the conflict in Ukraine.

With Kiev and the West accusing Russia of supporting the insurgency, Basescu has also called on NATO member states to "go beyond declarations of good intent" and pleaded for a "new level of sanctions".

NATO chief Anders Fogh Rasmussen has said that the 28-nation alliance will aim to approve a "readiness action plan" at the summit, which will see rotating troops and equipment deployed throughout Eastern Europe.

The force -- which he says will be thousands-strong -- could be deployed within days to meet any perceived Russian military movements in the region.