The Syria debate continued to heat up in Washington as different branches of US Government said they now have proof that the Assad regime carried out chemical weapons use attack.

Reports have also indicated that Donald Trump clashed with Secretary of Defense James Mattis over the scope and targeting mission of a potential US response.

Late on Friday, the White House held its fourth meeting this week to discuss Syria, attended this time by deputy Secretaries and advisers, according to spokeswoman Sarah Sanders.

Mr Trump called his French counterpart Emmanuel Macron earlier in the day. The two leaders have been coordinating very closely joint responses and actions on Syria and Mr Macron called the Russian President Vladimir Putin ahead of speaking to Mr Trump.

But in Washington, the debate on US options intensified amidst reports that Mr Trump is at odds with his defence chief over the military options in Syria.

The US President “is prodding his military advisers to agree to a more sweeping retaliatory strike in Syria than they consider prudent, and is unhappy with the more limited options they have presented to him so far,” reported the Wall Street Journal on Friday.

Unlike Mr Mattis who is concerned of retaliatory measures against the US and has been advocating a limited strike, Mr Trump “has been pushing for an attack that not only would punish the Syrian regime but also exact a price from two of its international patrons, Russia and Iran,” US officials told the paper.

_______________

Read more:

UN chief warns that Mideast 'chaos' threatens global peace

Russia blames UK for staging 'fake' Syrian chemical attack

International military action against Syria awaits Trump decision

_______________

“He wants Mattis to push the limits a little bit more,” the official said.

The National reported on Thursday that Mr Mattis presented limited strikes options to the US President yesterday, and none of them debilitate the Assad regime airpower.

Mr Trump was not happy with the options presented, prompting his defence secretary to cancel a trip to New York and hold meetings at the Pentagon to expand the list of potential responses.

Mr Mattis’ caution is largely driven by fear of retaliation from Russia or Iran or both, and being dragged into the Syrian civil war.

The Wall Street Journal revealed that “over the past two days, the Pentagon has had two opportunities to launch attacks against Syria in reprisal for a suspected chemical weapons attack, but Mr. Mattis halted them.” One of the attacks was scheduled for Thursday night.

According to the same report, Mr Trump is preoccupied with the Syria attack and response. “He has asked for briefing materials and was moved by images of children with foam bubbling from their mouths, symptoms of chemical weapons poisoning, aides said."

Mr Trump’s view on broader strikes is supported by most of his cabinet including his new national security adviser John Bolton, Ambassador to the UN Nikki Haley and Acting Secretary of State John Sullivan. Mr Bolton, who is known for his hawkish foreign policy record, “favours an attack that would be “ruinous,” crippling some part of Syrian President Bashar Al Assad’s government and national infrastructure” the paper said.

Nicholas Heras, a defence fellow at the Center for new American Security, told The National that the divisions over policy options within the Trump team implies that “there is an extraordinarily intense debate within the administration about the timing, and how hard to strike Mr Assad”.

The leaks of the differences “may mean that Secretary Mattis is losing the battle with the White House, and those around him want the record to show that he favoured more caution, if President Trump orders strikes that have significant consequences” Mr Heras said.

Those consequences “could include Russia attacking Americans in eastern Syria, Iran targeting Americans in Syria and Iraq or Israel, or the collapse of the Assad regime and chaos in Western Syria” the expert added.

On Friday as well, the State Department, the Pentagon and the White House said they have proof that the Syrian government was behind the attack.

The US has "a very high level of confidence" that the Syrian government carried out the attack, said Heather Nauert, the State Department spokeswoman.

United States Ambassador to the United Nations Nikki Haley greets her Russian counterpart Vasily Nebenzya before the UN Security Council meeting on Syria at the UN headquarters in New York. Eduardo Munoz/ Reuters

“We can say that the Syrian government was behind this attack... We know there are only certain countries, like Syria, that have delivery mechanisms and have those types of weapons” she added.

Asked if the United States has proof that the Assad government carried the attack, Ms Nauert said: "Yes."

"We believe we know who was responsible for this. We will still wait -- the Organisation for the Prohibition of Chemical Weapons (OPCW) will still formulate its facts and its findings, but it does not determine the responsibility, they determine the substance.”

Part of the OPCW team arrived in Syria on Friday.

In case you missed it: In response to media queries, the Spokesperson for the Organisation for the Prohibition of Chemical Weapons (OPCW) confirms that the #OPCW Fact-Finding Mission (FFM) team is on its way to #Syria and will start its work as of Saturday 14 April 2018. pic.twitter.com/IZUIpg2DsZ — OPCW (@OPCW) April 12, 2018

Ms Nauert said, however, that the US is still looking into “exact kind or mix” of the chemical agent used. If the mix includes a nerve agent such as Sarin gas or phosgene alongside chlorine, it could imply a harsher response. Mr Heras said the presence of a “nerve agent means an easier explanation to the American public for carrying the strikes.”

The World Health Organization estimated that 500 people from Douma had been treated for symptoms of gas poisoning, and 70 deaths in the shelters on the day of the attack.

There was no sign of a diplomatic breakthrough with Russia, or at the United Nations Security Council that met for a third open session on Syria on Friday.

“I’m in awe, Vasily, of how you say what you say with a straight face – I really, really am,” Ms Haley told her Russian counterpart, Ambassador Vasily Nebenzia.

“If Russia had lived up to its commitment, there would be no chemical weapons in Syria, and we would not be here today” Ms Haley said ahead of her return to Washington for the Syria meetings.

RT @USUN: “If Russia had lived up to its commitment, there would be no chemical weapons in Syria, and we would not be here today.” pic.twitter.com/re7XiE2jnJ — Nikki Haley (@nikkihaley) April 13, 2018

Russia accused the United Kingdom of staging the attack, to which the UK respondent by calling the accusation a “blatant lie.”

Still, the response to the attack awaits Mr Trump’s decision. “If you rush decisions like this, you make a mistake,” Ms Haley said

But even as the White House was taking its time, the US navy increased its presence in the region. US guided-missile destroyer USS Winston Churchill “entered the Navy’s area of operations that includes the Mediterranean” Bloomberg reported.

More US aircrafts were also visible near Syria:

US Navy P-8A 168439 PS056 departed NAS Sigonella - Eastern Mediterranean mission: On task West of Lebanon & Israel pic.twitter.com/OiK3WkEaHT — Aircraft Spots (@AircraftSpots) April 12, 2018

Both Mr Trump and Mr Mattis cancelled their travel plans to be in Washington this weekend.