The U.S. is frantically trying to salvage a Syrian opposition conference set for this week in Rome that U.S. Secretary of State John Kerry plans to attend.

A senior Obama administration official says Kerry has sent his top Syrian envoy to Cairo in hopes of convincing opposition leaders that the conference will be critical to securing additional aid from the United States and Europe.

Some members of the sharply divided Syrian Opposition Council are threatening to boycott Wednesday's meeting.

The official says U.S. envoy Robert Ford will say the conference is a chance for foes of Syrian President Bashar Assad to make their case for new and enhanced aid — especially to Kerry. He's on his first overseas trip as secretary of state.

The official was not authorized to discuss sensitive diplomatic matters publicly and spoke on condition of anonymity.