Such an evolution in Tehran would lead to a withdrawal of Iranian support for Hezbollah and other radical groups, thereby isolating Syria and reducing pressure on Israel.

The United States, which considers Syria a state sponsor of terrorism, has struggled to isolate Syria as a strategy to change it.

Washington has a policy of isolating Syria.

Casting the American vote on Monday will be Secretary of State Condoleezza Rice, the leader of the American diplomatic campaign to isolate Syria.

The conference offers rare high-level contact between the United States and two governments it has tried to isolate, Iran and Syria, but how extensive their discussions will be is far from clear.

But Washington has spent years trying to isolate Syria, while Iran has for decades moved to entwine itself with Syria on many levels - political, military, economic and religious.

If so, that, too, could antagonize Washington, which wants to isolate Syria further.

He said the Bush administration's effort to isolate Syria "has seen nothing but failure."

We do not wish to isolate Syria.

Mr. Assad said the Bush administration's attempt to isolate Syria "has seen nothing but failure."