BUCHAREST: The first US troops reinforcing NATO allies on the eastern flank following a Russian military build-up on Ukraine's border have arrived in Romania, Defence Minister Vasile Dincu said on Tuesday.

The United States is sending nearly 3,000 extra troops to Poland and Romania to shield Eastern Europe from potential spillover from the Ukraine crisis.

The Pentagon said it will relocate a Stryker squadron of around 1,000 US service members from Vilseck, Germany to Romania. In Poland, troops began arriving on Saturday.

Dincu told reporters the first 100 US troops were in Romania handling logistics.

"The Americans have arrived," he said. "Over 100 specialist US soldiers together with our logistics specialists are preparing, which means it will not be long before the rest of the troops arrive."

First US reinforcement troops for Europe arrive in Germany

The US currently has about 900 soldiers in the country, a NATO member since 2004 and host to a ballistic missile defense system, some as part of the NATO force and some under separate bilateral arrangements.

France said it also plans to send troops to Romania and has offered to be the lead nation of a future NATO mission, which could see about 1,000 troops from various countries.

A decision could be made at the next NATO defence ministers meeting in mid-February.

NATO is considering a longer-term military posture in eastern Europe to strengthen its defences, Secretary-General Jens Stoltenberg said on Monday. The alliance currently has troops rotating in and out of eastern Europe.