NATO defence ministers agreed in Brussels on Wednesday to increase the alliance's presence in eastern Europe but without setting up new military bases, NATO Secretary-General Jens Stoltenberg said.
Stoltenberg made the announcement after a meeting of the defence ministers of NATO's 28 member-countries.
Croatian Defence Minister Josip Buljevic expressed satisfaction with that decision.
"We especially look forward to the increased presence of US troops in Europe. As of now, the United States will be more active and more present in that part of the world... that gives rise to optimism," Buljevic said.
The soldiers "will be multinational to make clear that an attack against one ally is any attack against all allies and that the alliance as a whole will respond," Stoltenberg told a news conference following the first session of the two-day defence ministers' meeting.
Troops from multiple countries will rotate in and out of eastern European member states rather than being permanently based there, and military experts are expected to recommend this spring the size and make-up of those forces.
Stoltenberg said that he would meet in Munich this week with Russian Foreign Minister Sergei Lavrov to inform him that this was part of NATO's defence strategy for the Baltic and eastern Europe.
He added that in the current difficult times it was even more important to have political dialogue and open channels of communication between NATO and Russia.
It is said that NATO could have a 1,000-member brigade in each of the six eastern European countries - Estonia, Latvia, Lithuania, Poland, Bulgaria and Romania. The brigades would have rapid reaction support including air, land and naval forces numbering around 40,000 troops.
NATO says that it will honour a 1997 agreement with Russia whereby it pledged not to have combat troops in eastern Europe.
Buljevic would not speak of any figures, saying that they were yet to be discussed.
Asked if the defence ministers discussed NATO's possible participation in supervising the sea border between Greece and Turkey to prevent the smuggling of migrants, Buljevic said that the topic was discussed only informally on Wednesday and that it would be discussed on Thursday.
"That's not NATO's primary task but NATO will find a way to help the EU," he said.