The United States on Wednesday said it would pull some troops out from NATO's eastern flank but denied the move amounted to an American withdrawal from Europe.

Romania's defence ministry said 900-1,000 US soldiers would remain in the country, down from the about 1,700 currently being deployed in the Black Sea nation.

During a visit to the EU and NATO member bordering war-torn Ukraine on Thursday, French Defence Minister Catherine Vautrin said that France remains committed "to the collective defence of the European continent".

The presence of 1,500 French troops in Romania was an expression of France's commitment, she said.

"The French Armed Forces are present in Romania, at the heart of the Eastern flank, in an international security context which is... very deteriorated," she said during a joint press conference with her Romanian counterpart Ionut Mosteanu.

"They embody our concrete commitment... for the security of Romania, for the security of Europe, and for the security of France and the French people," she said.

Vautrin added that France's commitment is "not temporary" but "long-term and based on trust... This message of stability is key for our Romanian friends as well as for the entire eastern flank".

Mosteanu said his country would acquire Mistral 3 surface-to-air missiles "under a contract to be signed by the end of this year" as part of the European Joint Acquisition Initiative led by France.

According to a spokesperson for Romania's defence ministry, the contract could be worth 660 million euros ($760 million) excluding VAT.

Since October 20, France has been participating in NATO's Dacian Fall military exercise in Romania.

The exercise "is a clear signal that we want to send together: Europe is ready," Vautrin said.

It is "further proof of the European allies' commitment to the security of Romania, the Black Sea and the eastern flank," said Mosteanu.