The US has reported to Russia about the parts of Syria in which its special forces are active, and asked that Moscow not attack those areas.
"We provided a geographical area that we asked them to stay out of because of the risk to US forces," said a spokesperson for the Pentagon. "This was a step we took to try to maintain their safety in a dangerous situation and this was a request that we made to the Russians outside the scope of the" memorandum of understanding signed last October.