President Obama called the suspected Syrian poison-gas attack “clearly a big event, of grave concern” — but downplayed the chance of any US military response.

In his first public comments on the reported deaths of 1,300 people on Wednesday, Obama said the Syria civil war was “troublesome.”

But asked on CNN yesterday about his warning that the use of chemical weapons would be a “red line,” he said:

“If the US goes in and attacks another country without a UN mandate and without clear evidence that can be presented, then there are questions in terms of whether international law supports it.”