UPDATE 2 - Trump to make decision on Syria within 2 days

ADDS WHITE HOUSE COMMENT, MCCAIN STATEMENT IN GRAPHS 11-15

By Michael Hernandez

WASHINGTON (AA) - The U.S. will decide on its response to a suspected chemical attack in Syria within the next day or two, President Donald Trump said Monday.

Trump later said his decision will "probably" be made today.

"This is about humanity and it can’t be allowed to happen,” Trump said at the White House. "If it’s the Russians, if it’s Syria, if it’s Iran, if it’s all of them together, we’ll figure it out.”

The comments come as Trump prepares to convene with his top military brass Monday night for a working dinner expected to be focused on Washington's response to a reported chemical attack in which dozens of people were killed Saturday night outside of Damascus.

The White Helmets, a local civil defense agency, blamed the Syrian regime for the attack in Eastern Ghouta's Douma, which, it said, killed 78 civilians and injured hundreds of other victims.

The Organization for the Prohibition of Chemical Weapons (OPCW) confirmed its fact finding mission is investigating "to establish whether chemical weapons were used".

The U.S. has long maintained Russia ultimately bears responsibility for any chemical attacks carried out by the regime because Moscow is Bashar al-Assad's principal international backer.

Asked if Russian President Vladimir Putin bears responsibility for this weekend's suspected chemical attack, Trump said Putin "may" be held responsible.

"If he does it’s going to be very tough, very tough," Trump said. "Everybody’s gonna pay a price. He will, everybody will."

Trump insisted military action is not off the table one day after Russia's U.S. embassy warned it "may trigger the gravest consequences".

Earlier Monday, Senator Lindsey Graham urged Trump to take action against the Syrian air force, saying Assad "is a legitimate war criminal in the eyes of the international community".

"We should make [Assad] pay a heavy price by destroying his air capability," Graham told Fox News.

The White House pushed back on suggestions Trump is to blame for the deadly Douma attack after he signaled that the U.S. would pull out its forces from Syria.

"It is outrageous to say that the president of the United States green lit something as atrocious as the actions that have taken place,” spokeswoman Sarah Huckabee Sanders told reporters.

In a terse statement, senior Senator John McCain laid the blame for the alleged chemical attack on Trump, saying Assad, Russia and Iran "heard him" when Trump voiced his intent to leave Syria "very soon".

Reiterating Trump's comments over the weekend White House spokeswoman insisted "there will be a price to pay" for the Douma attack.