Syria: Pentagon asked Russia to avoid bombing US commandos

US officials asked Russia to avoid bombing areas of northern Syria where several dozen US special operation forces have been working with Syrians fighting the Islamic State group (IS), the Pentagon disclosed on Thursday.

The request, which had not been revealed previously, goes beyond what the Pentagon calls its "memorandum of understanding" with the Russians to avoid inadvertent military air collisions over Syria.

Pentagon press secretary Peter Cook said the Russians were not told exactly where the US special operations troops are operating but were asked to avoid certain broad areas as a safety measure. He said the Russians have honoured the US request.

"We've told them these are areas that we have coalition forces in - general areas where we have coalition forces," commander of US Air Forces Central Command Lt. Gen. Charles Q. Brown told reporters at the Pentagon from his headquarters in Qatar.

"We don't want them to strike there because all it's going to do is escalate things. And I don't think the Russians want to escalate against the coalition."

Brown said the Russians have identified airfields in Syria "that they don't want us flying close to." He said those are beyond where US planes normally operate, "so that hasn't been an issue."

Cook would not say when the US request was made or who in the Pentagon made it.

"I'm not going to get into details other than to say that there was an effort made to protect the safety of our people from the risk of Russian airstrikes," Cook said. "And that those steps were taken, and those so far have been honored."

US-Russian military relations have been strained by the Syria war, with the Obama administration contending that the Russians are propping up the Syrian government of President Bashar Assad rather than fighting the Islamic State.

Agencies contributed to this report