"That is one of the ideas that's under discussion," Carter told reporters yesterday flying with him from Washington to Stuttgart, Germany, where he is to preside Tuesday at a ceremony installing a new commander of US European Command.
Army Gen Curtis Scaparrotti is to replace Air Force Gen Philip Breedlove, who has frequently and publicly cautioned that Russia poses a potential threat to European stability.
Carter said the allies are considering a rotational ground force of four battalions, which would mean about 4,000 troops. That would be in addition to, and separate from, a recently announced unilateral US decision to send a US armoured brigade of about 4,200 troops to Eastern Europe next February.
Russia has accused the US and NATO of returning to a Cold War mindset of mutual suspicion and military competition, even as it continues to buzz US ships and planes in the Baltics.
Speaking more broadly of US and NATO relations with Russia, Carter said Moscow has chosen to move away from integration with the West. "Therefore, we have no alternative but to do what we're doing, which is stand strong," by improving the US military posture in Europe and collaborating closely with NATO allies, he said.
In his remarks en route to Stuttgart, Carter also called the buzzing of US Navy ships and aircraft in the Baltics "unprofessional," adding that it seems to be happening more frequently.
"This kind of unprofessional behaviour by its nature creates a dangerous circumstance," he said.
At the Pentagon on Monday, the Navy's top officer said the Russian actions in the Baltics are escalating tension between the two nations.
"I don't think the Russians are trying to provoke an incident. I think they're trying to send a signal," he said.
"I think it's pretty clear that they are wanting to let us know that they see that we are up there in the Baltic.
