US Secretary of State Antony Blinken met in Rome with representatives of the 83-member coalition against the Islamic State (IS).
US officials have largely carried over the approach developed during the Trump administration, namely leaving US troops to indefinitely occupy oil-rich northeast Syria while economically isolating the regime of President Bashar al-Assad.
The policy remains in limbo amid indirect negotiations with Iranian officials in Vienna.
A new UN vote in the Security Council is set to renew the UN mandate to deliver cross-border aid into Syria from Turkey. Russia has sought to block such aid, insisting that the Damascus government only deliver.