The U.S. stance on striking Syria is no clearer, even after President Trump tweeted that missiles "will be coming". Trump himself appeared to place blame on the Assad regime, tweeting shortly after the attack that the Syrian president was behind "another humanitarian disaster for no reason whatsoever".
Mr Trump warned Russian Federation on Wednesday to "get ready" for a missile attack on its ally Syria.
Syria and its backers, Russian Federation and Iran, say reports of the attack were fabricated by rebels and rescue workers in Douma and have accused the United States of seeking to use it as a pretext to attack the government.
Asked about the risks of USA military retaliation, Mattis cited two concerns, starting with avoiding civilian casualties. Russia's ambassador to Lebanon said any missiles fired at Syria would be shot down and the launching sites targeted - a stark warning of a potential major confrontation in Syria.
Rep. Adam Smith, the ranking Democrat on the House Armed Services Committee, said he sees no legal justification for a USA strike in Syria, absent explicit authorization by Congress.
The White House announcement came after May held an emergency cabinet meeting on the situation in Syria, where dozens of people were killed last weekend in a suspected toxic gas attack on Douma, the largest town in a former rebel stronghold outside Damascus.
PARIS: Western strikes against the Syrian regime in retaliation for the use of chemical weapons could affect Bashar al-Assad´s military apparatus and push Russian Federation to return to the negotiating table, but also spark tensions in the region, according to experts.
Trump has slammed Russian Federation for its partnership with "Gas Killing Animal" Assad, spurring concerns that a United States strike could lead to a conflagration with Russian Federation, which has major military facilities at Tartus and Khmeimim and works cheek-by-jowl with Syria forces that could be targeted.
UFC 223 breaks Barclays Center attendance record, Jedrzejczyk believes she won
Judges scored the fight 50-44, 50-43, and 50-43, meaning Nurmagomedov earned two 10-8 rounds on two of the judges' scorecards. Rose had great head movement and I was surprised at how few leg kicks Joanna used in the fifth round.
Mattis, however, indicated on Wednesday that evidence of what happened was still being studied.
"Those two things, I'm assured, we will get an answer to today", he said of Thursday's cabinet meeting. This is in contrast to an incident one year ago in which the US government had video and other evidence of certain aspects of an actual attack by Syrian aircraft, which involved the use of sarin gas. Some 59 Tomahawk cruise missiles were fired at an airfield that was a base for Syrian fighter jets, radar equipment and air defense systems.
On Friday campaigners from the Stop the War Coalition will hand in a letter signed by MPs, trade unionists, celebrities and academics to Downing Street urging Mrs May to not take military action in Syria. The allies are working to decide what response would be "useful and efficient", Macron said in a television interview. We are totally predictable. That meant airstrikes, possibly in tandem with France and other allies that have expressed outrage at the alleged Syrian chemical attack, could be launched within hours of a presidential decision.
The U.S. Navy Arleigh Burke-class guided-missile destroyer USS Donald Cook sails in the Bosphorus strait in Istanbul, Turkey August 28, 2015.
It was not clear whether Trump and USA allies would wait for the results of the investigation before deciding on a strike. Trump canceled a foreign trip in order to manage a crisis that is testing his vow to stand up to Assad.
That, in part, may be the reason Trump sent his threatening tweet early on Wednesday. The US bombs would be "nice and new and "smart", he added.
Syria and its ally Russian Federation deny such an attack happened.
The Syrian Observatory for Human Rights, a British-based war monitor, also said pro-Syrian government forces were emptying main airports and military airbases.