The first batch of US troops -- meant to bolster NATO's eastern flank amid fears of a Russian invasion of Ukraine -- have arrived in Romania, the country's defence minister said on Tuesday.

US President Joe Biden announced last week that he is sending 1,000 soldiers to Romania and 2,000 to Poland, as Russia refuses to pull back troops poised on Ukraine's borders.

"More than 100 US soldiers, specialists, who are preparing this deployment, have arrived," Romanian Defence Minister Vasile Dancu told reporters.

"It won't take long until the rest of the troops will arrive," he added.

The Pentagon has said that the Stryker Squadron to be relocated to Romania was coming from Vilseck, Germany.

The first batch of US soldiers arrived in Poland over the weekend with the bulk of the contingent to follow.

France's President Emmanuel Macron has also said he's ready to send hundreds of troops to Romania under NATO command.

French experts preparing the deployment have already arrived in Romania, France's Defence Minister Florence Parly said last week in Bucharest.

Romania, a NATO member since 2004, already hosts around 900 US troops, as well as 140 Italian and 250 Polish troops.