The United States gathered ministers from key allies to push for a political settlement in Syria on Monday, but gave short shrift to a French call for a new contact group to resolve the conflict.

Meeting in New York at the invitation of US Secretary of State Rex Tillerson, the so-called "like-minded" group of mainly NATO and Arab allies, agreed to urge the parties to the war to negotiate a political transition.

And they warned that neither Syrian strongman Bashar al-Assad nor his Russian and Iranian backers could expect the world to recognize the regime nor fund the country's reconstruction without a path to a settlement.

But a call from France for a new diplomatic "contact group" to bring in the key players in the drama to oversee a peace process fell foul of Washington's opposition to working with Iran. 

"There was no discussion of other fora in this session," US acting assistant secretary of state David Satterfield told reporters after the meeting, held in a hotel on the sidelines of the UN General Assembly.

The Netherlands' Foreign Minister Bert Koenders confirmed that the French idea "wasn't discussed." 

"If the contact group had Iran in it, that would be difficult for us," a senior US official told AFP after the meeting, speaking on condition of anonymity to explain the American position.

Earlier, French Foreign Minister Jean-Yves Le Drian had said France would call a meeting of the five permanent members of the UN Security Council on Thursday to discuss developing a group "bringing together the main actors in the conflict."

"We must now begin a political process, and for that we must get off the paths that have not led us to a solution since 2011," he told a news conference.

For the Americans, Satterfield admitted that the search for a political solution had not made much progress since the July 2012 Geneva conference on Syria agreed on the principle of a transitional government.

- Reconstruction funds -

But he insisted that after five more years of bloody war, the actors on the ground are now broadly ready to accept that they must re-engage with the UN-backed peace process, seeking a deal with Syrian public support.

"There is a recognition in Syria, we believe, by all parties that the violence has to come to halt, and that through the ending of violence a political process must begin," he said.

"Five years ago there were a mix of very different goals and objectives and in tactics to get them."

Satterfield also warned, in words echoed by British Foreign Secretary Boris Johnson, that no international reconstruction funds would be forthcoming until fighting ends and a credible peace process begins.

"We also believe that the only way forward is to get a political process going and to make it clear to the Russians to the Iranians and to the al Assad regime that we, the like-minded group, we will not support the reconstruction of Syria until there is such a political process," Johnson told reporters.