A U.S. State Department official says the United States is reviewing an invitation to attend Syria peace talks planned later this month in Kazakhstan's capital of Astana.
The official told Reuters that Washington did receive an invitation and that it is "under review."
Russian Foreign Minister Sergei Lavrov has said that Moscow invited the United States to attend the talks, which are due to start on January 23 -- three days after U.S. President-elect Donald Trump is sworn into office.
The meeting is being sponsored by Russia and Iran, both allies of Syrian President Bashar al-Assad, and by Turkey.
Delegates from Moscow, Ankara, and Tehran plan to participate along with representatives of the United Nations.
One of Syria's most powerful rebel groups, the Islamist Ahrar al-Sham, says it will not attend.
Iran has said it opposes the presence of U.S. delegates.
Trump has sharply criticized the Iranian government and its nuclear deal with world powers that took effect a year ago.