US not ready to collaborate militarily with Russia, says Trump's defence secretary

The US is not ready to collaborate militarily with Russia, defence secretary Jim Mattis said, appearing to close the door for now on any effort to work more closely with Moscow in the fight against Islamic State militants in Syria.

His blunt rejection came after Russian President Vladimir Putin called for increased intelligence co-operation with the US and Nato, and it makes such co-ordination less likely, at least in the near future.