National security adviser H.R. McMaster on Sunday said Russia should question its support for Syrian President Bashar Assad.

"Russia should ask themselves, 'What are we doing here?'" he said on "Fox News Sunday."

"'Why are we supporting this murderous regime that is committing mass murder of its own population and using the most heinous weapons available?'"

ADVERTISEMENT

McMaster said the renewed focus on Syria is a good opportunity for Russian leadership to re-evaluate what it is doing.

"Russia could be part of the solution," he said, adding that now, much of the world thinks Russia is "part of the problem."

He said the relationship between the U.S. and Russia today will be "whatever the Russians wants it to be."

"Do they want it to be a relationship of competition and potential conflict? I don't see how that's in Russian interests. Or do they want it to be a relationship in which we can find areas of cooperation that are in mutual interests?" McMaster asked.

"How is it in anyone's interest that this conflict in Syria and this catastrophe in the greater Middle East continues, and they can be part of the solution."

Last week, the U.S. launched a missile strike on a Syrian military air base in retaliation for a chemical attack in northern Syria earlier that the U.S. has blamed on the administration of Syrian President Bashar Assad.