US and Russia 'can co-operate over IS'
In the wake of the Paris attacks and increased strikes on Islamic State sites in Syria and Iraq, the former US Secretary of Defense says now is the time for the US and Russia to work more closely together.
William Cohen tells the BBC's Babita Sharma that while the US will always have some differences with Russia, the two sides can find common ground in their fight against the militant group.
"Terrorism threatens them as much as it threatens us", says Cohen.