Trump took credit for that deal, but so far has not weighed in, although Ortagus said the White House was "fully supportive" of the State Department's warnings.
One powerful rebel group struck back Wednesday. Al Nusra Front, which was at one time affiliated with al Qaeda, launched an offensive on a Russian air base with around 500 fighters, seven tanks, and around 30 heavy machine-gun mounted pick-up trucks, according to Reuters news agency.
(MORE: Former ISIS stronghold Raqqa struggles to recover after years of war) The attack will likely prompt an even stronger military response from Assad, who U.S. officials say believes he can still win the eight-year old war through force.
That's a view that virtually everyone else has abandoned, according to U.S. Special Representative for Syria James Jeffrey, who said that gives him hope.
"Everybody wants this war to end, everybody wants refugees and [internally displaced persons] to return, and everybody wants the fighting and this danger of an escalation to stop," Jeffrey told the House Foreign Affairs Committee Wednesday, with one exception: Assad himself, who has "shown little willingness to be flexible on any issue and at the moment may be concluding that it's better to sit on a pile of rubble with half his population and 60 percent of his country than compromise."
To that end, Russia has been helpful, according to Jeffrey, who said Moscow knows they need a political solution to rid themselves of the costly conflict and an ally that most of the rest of the world opposes. Pompeo made that clear with a "very strong démarche," per Jeffrey, when they met Putin in Sochi last Tuesday.
(MORE: Coalition strikes killed 1,600 civilians in Raqqa says new report) "We received assurances from the Russians, some of which they seemed to have been trying to carry out in the days since we were in Sochi. Trying to slow down or stop any military conflict with dozens of groups on the ground is not easy... But we did believe that we made some progress with President Putin," he added.
U.S. sanctions and a promise by America and its allies to withhold any reconstruction funds until Assad allows for a political transition has been instrumental in influencing Russia and key to that future path, Jeffrey said. To that end, he urged Congress to continue to apply economic pressure, including passing the Caesar Syria Civilian Protection Act.
The bill, which was approved by the Senate Foreign Relations Committee Wednesday, would require the president to sanction anyone who does business with the Syrian government or central bank, including those involved in construction, engineering, or energy projects or those providing aircraft or spare aviation parts. It also authorizes the State Department to support the collection and preservation of evidence of war crimes or crimes against humanity to aid in any future investigations and trials.
The bill, which takes its name from the code name of a military defector who smuggled 53,275 photographs out of Syria showing Assad's war crimes, passed the House in January.
ABC News's Matt McGarry contributed to this report from Dubai.
Kaynak:Abcnews