The White House says Syrian President Bashar Assad's government is responsible.

"The likelihood of exposure to a chemical attack is amplified by an apparent lack of external injuries reported in cases showing a rapid onset of similar symptoms, including acute respiratory distress as the main cause of death", the United Nations agency said.

Experts say only the Assad regime or its Russian sponsors have the aircraft capable of conducting such an attack. "These heinous actions by the Bashar al-Assad regime are a effect of the past administration's weakness and irresolution".

At a joint press conference with Jordan's King Abdullah II Wednesday, Trump said that his attitude about Syria's President Bashar Assad and about Syria has "changed very much". He added, "I think, at this point, as things develop, I'm not ready to talk about our next step, but we'll get there soon".

Obama, too, faced a dearth of good options in Syria, which he has often acknowledged as the biggest failure of his presidency.

A former US ambassador to Russia on Wednesday urged Secretary of State Rex Tillerson to ask Russian President Vladimir Putin if he misled the global community on Syria.

The blame on Assad may implicate the regime's staunchest ally and military supporter in Moscow.

"Russia can not escape responsibility for this", she added.

"This is the administration in charge".

The US president for the second time in two days blamed the Assad regime for the crime.

The attack Tuesday in rebel-held northern Idlib is responsible for the deaths of dozens of people, including women and children.

Syria's army has denied any use of chemical weapons, saying it "has never used them, anytime, anywhere, and will not do so in the future".

Yet at the time, Trump was squarely in agreement with Obama's ultimate decision. Mr Obama's spokesman declined to comment.

However, in typical Trump fashion, the United States president kept it vague on whether he will take action in Syria. Haunting images of lifeless children piled in heaps reflected the magnitude of the attack, which was reminiscent of a 2013 chemical assault that left hundreds dead and was the worst in the country's ruinous six-year civil war.

The U.N. Security Council plans an emergency session midday Wednesday on the attack. The officials weren't authorized to speak publicly on the matter and demanded anonymity.

The United Nations Security Council will be briefed, at the request of Britain and France, on a suspected chemical weapons attack in Syria that killed dozens of people, including 11 children, in the northwestern province of Idlib.

Both the Syrian and Russian governments deny the attacks, saying that gas leaked from a rebel warehouse that was hit by bombs.

"We condemn the use of chemical weapons in all circumstances".

A US official said an American review of radar and other assessments showed Syrian aircraft flying in the area at the time of the attack. Washington hasn't yet concluded what type of chemical was used.

There are competing forces pulling at the Trump administration as it faces one of its first major foreign crises.

Jordan has been part of a US -led military coalition against ISIS for the past two years, hosting Western military trainers and carrying out airstrikes against ISIS targets. "The illegitimate Syrian Government, led by a man with no conscience, has committed untold atrocities against his people", United States ambassador to the UN Nikki Haley told the 15-member council.

But America's Arab and European allies oppose any accommodation with Assad.

"For the past three years the OPCW has worked with the Syrian Arab Republic to assess and verify their declaration".

 source: AFP