The UN's Syria envoy said Thursday that he will hold talks with Russian officials next week but without the US present after previous plans for a trilateral meeting were "postponed".
UN peace mediator Staffan de Mistura said his meeting with Russia's deputy foreign minister Gennady Gatilov is set for Monday in Geneva.
"The trilateral meeting is not off the table, it is simply being postponed", de Mistura told reporters.
Asked why US President Donald Trump's representatives decided to skip the meeting, de Mistura said: "you should ask them, frankly."
Syrian regime supporter Moscow and opposition-backer Washington had been the key foreign powers shaping the UN's Syria peace process.
De Mistura has previously asked for more clarity from Trump's administration on its vision for the Syria talks.
US officials have in recent weeks voiced commitment to support a negotiated solution to the conflict.
Monday's sitdown with Gatilov "will be a very intense bilateral meeting", de Mistura said.
He also restated his desire to convene a sixth round of UN-backed talks involving Syrian rivals next month.
The previous rounds have failed to produce concrete results.