WASHINGTON • Despite dire U.S. warnings and fears of a humanitarian disaster, the Trump administration has little leverage to stop Russia, Iran and Syria pressing ahead with a massive military assault against Syria’s northwest Idlib province.

Washington has threatened military action in case of a chemical weapons attack but its mixed messaging on retaining a U.S. presence in Syria and a cut in aid has diminished its already limited influence over the seven-year conflict.

So the administration, which has criticized former President Barack Obama for his inaction on Syria after the war started in 2011, risks appearing powerless to prevent the three nations’ plan to retake Syria’s last rebel-held area. It’s an operation that many warn will cause major bloodshed among a vulnerable population of 3 million people.

And on Saturday, Syrian government and Russian warplanes targeted the province’s southern edge in what activists described as the most intense airstrikes in weeks. More than 60 air raids killed at least four civilians in southern Idlib, according to the Syrian Observatory for Human Rights and rescue workers.

While the new U.S. special envoy for Syria said this week America will stay in Syria until the complete eradication of the Islamic State group, there’s little assurance that President Trump won’t again seek the withdrawal of the roughly 2,000 U.S. troops in the country. And in a sign of the administration’s shrinking commitment to Syria, it has pulled more than $200 million in stabilization funding for liberated areas, telling other nations they should step up to pay.

A summit in Tehran on Friday between Russian President Vladimir Putin, Iranian President Hassan Rouhani and Turkish President Recep Tayyip Erdogan was seen as a chance for a diplomatic solution before a full-scale assault on Idlib. The three nations are all tacitly allied against IS and in support of a unified, stable Syria, but have differing views of how to achieve those ends.

After Friday’s talks, the U.N. envoy for Syria told the U.N. Security Council there were indications that the three leaders intend to continue talking to avoid a catastrophe. But above all, the summit highlighted the stark differences among these allies of convenience, with Putin and Rouhani opposing Erdogan’s call for a cease-fire.

As they discussed the fate of Idlib, U.S. Ambassador to the United Nations Nikki Haley was talking tough in New York, telling the Security Council the U.S. would consider any assault on the province as a “dangerous escalation” of the conflict that has already claimed more than 400,000 lives and forced more than 5 million Syrians to flee.

“If (Syrian President Bashar) Assad, Russia, and Iran continue, the consequences will be dire,” said Haley, who was chairing the council meeting.

Those remarks capped a week of rising U.S. rhetoric opposing the Idlib operation.

On Monday, Trump tweeted: “President Bashar al-Assad of Syria must not recklessly attack Idlib Province. The Russians and Iranians would be making a grave humanitarian mistake to take part in this potential human tragedy. Hundreds of thousands of people could be killed. Don’t let that happen!”

A day later, Secretary of State Mike Pompeo expanded on the tweet, and renewed calls for the conflict to be resolved through the stalled U.N.-led Geneva Process. And on Thursday, veteran diplomat James Jeffrey, reiterated Trump’s message, saying the U.S. would use all the “tools” it has to respond to a chemical attack.

A Syrian students play last month in the courtyard of a school whose walls are still charred and pockmarked with bullets from recent fighting in the town of Douma, in the eastern Ghouta region, near the Syrian capital Damascus, Syria. Despite dire U.S. warnings and fears of a humanitarian disaster, the Trump administration has little leverage to stop Russia, Iran and Syria pressing ahead with a massive military assault against Syria’s northwest Idlib province.

the associated press