Defense Secretary Jim Mattis took a more measured tone, saying the US and its military coalition partners were still studying intelligence on the attack.
Last week, Trump advocated pulling US troops out of the country altogether, a drastic move strongly opposed by top military officials.
Meanwhile, The Telegraph has reported that British submarines are being moved within "missile range" of Syria- and that military action could start on Thursday night.
But John Glaser, director of foreign policy studies at the libertarian Cato Institute, said Mr. Trump should "back down" from his threats of an attack against Syria.
Meanwhile, Democratic Sen. Chris Murphy of CT warned that an attack wouldn't help end the civil war in Syria and said Trump must seek approval from Congress before attacking Syria.
Russian PM orders govt to draw up response to U.S. sanctions: Ifax
The official currency rates, announced by the Central Bank of Russian Federation on April 11, are 76,8522 rubles for euro and 62,3699 for a dollar.
In the midst of a continued investigation into the possibility that Russian Federation meddled in the 2016 US presidential election on Trump's behalf, Vladimir Putin's support of the Syrian regime has created a new rift between the controversial heads of state.
Trump appeared to soften his rhetoric in a follow-up tweet Wednesday morning, saying there is "no reason" for the US's worsening relationship with Russian Federation and that "we need all nations to work together".
Soon after the tweets, Russia's foreign ministry said that "smart missiles should fly towards terrorists, not legal government".
Trump a year ago ordered a strike against Assad following a deadly sarin gas attack on the rebel-held town of Khan Sheikhun.
Tiger Woods taking 3-to-4 weeks off after Masters
Asked after the round if Spieth knew where his score placed him, the 2015 champion replied: "I didn't look at one board". American Charley Hoffman aced the par-3 16th with a 6-iron, the 20th time the hole has surrendered a hole-in-one.
Flights from the Gulf will be affected more than others, with expected delays of 30 to 40 minutes, because instead of flying over northern Syria they will travel over Egypt's Sinai Peninsula and then on to the Gulf.
President Trump said Sunday that there would be a "big price to pay" for the poison gas attack that killed dozens of Syrian civilians, and he issued a rare public rebuke to Russian President Vladimir Putin for backing Assad in the country's civil war.
The Prime Minister sidestepped questions over whether she was concerned about the U.S. president's tweet.
May has not confirmed whether Britain will participate directly, but moved closer to it Wednesday, saying "the continued use of chemical weapons can not go unchallenged". Most carriers, however, have long avoided Syrian airspace after prior warnings by the United States and several European governments.
A watchdog agency, the Organization for the Prohibition of Chemical Weapons, announced that it would "shortly" send a fact-finding mission to Douma, after receiving a request from the Syrian government and its Russian backers to investigate the allegations.
Rockies star charges the mound and wild brawl breaks out
Rockies: OF Charlie Blackmon was out of the lineup for a second straight game with tightness in his right quad. The Rockies begin a four-game series against the pitching-rich Nationals with Bettis on the mound.