The US House Speaker Nancy Pelosi says Syria's President Bashar al-Assad has assured her in talks that he is ready to resume peace talks with Israel.
In Damascus, Ms Pelosi also said she gave Mr Assad a similar message from Israeli Prime Minister Ehud Olmert.
She also voiced concerns over Syria's alleged connections to Hamas and stressed Damascus' role in peace talks between the Palestinians and Israel.
Her visit angered President Bush, who said it undermined US foreign policy.
Mr Bush has said Ms Pelosi's trip to Syria sent "mixed signals" that undermined US-led efforts to isolate the Syrian president.
Speaking in Damascus after the talks, Ms Pelosi praised Mr Assad's attitude towards Israel.
"We were very pleased with the assurances we received from the president that he was ready to resume the peace process," she said.
"He's ready to engage in negotiations for peace with Israel. The meeting with the president enabled us to communicate a message from Prime Minister Olmert that Israel was ready to engage in peace talks as well."
She said that she and other members of her congressional delegation raised concerns about Israeli soldiers held captive by Hamas and Hezbollah.
Syria's relationship with the militant Islamist groups was also discussed, she said, as well as the issue of fighters illegally entering Iraq from Syria.
Earlier, Ms Pelosi met Foreign Minister Walid al-Moualem and Vice President Faruq al-Shara.
Ms Pelosi is reported to be the highest-ranking US politician to visit Syria since bilateral relations deteriorated in 2003, when the US invaded neighbouring Iraq.
Speaking on Tuesday Mr Bush was sharply critical of her visit, describing Syria as a "state sponsor of terror", and not part of the mainstream of the international community.
Ms Pelosi's office has said it is worth engaging with "every country that has an interest in avoiding a chaotic Iraq".
The bipartisan Iraq Study Group recommended last year that the US should begin direct talks about Iraq with both Iran and Syria - something the White House has rejected.
But Ms Pelosi is not the first member of Congress to visit Syria - some Republicans have been there too.
Daniel Serwer, of the Iraq Study Group, said the row in Washington appeared to be about the two sides drumming up support for the impending battle over whether to set a deadline for the withdrawal of US troops from Iraq - which Democrats are demanding but Mr Bush has rejected.
The Bush administration has boycotted Syria since the 2005 murder of Lebanon's former PM Rafik Hariri.
A UN investigation has implicated Syrian officials in the killing of Mr Hariri, despite a strong denial from Damascus.
In the past, Israel has tied peace talks with Syria to Damascus ending support for Hezbollah in Lebanon and hard-line Palestinian groups.
For its part, Syria has demanded the return of the Golan Heights occupied by Israel in 1967.