Nawaf Fares, a former provincial governor, is the second prominent Syrian to break with the regime in less than a week. Brig. Gen. Manaf Tlass, an Assad confidant and son of a former defense minister, fled Syria last week, buoying Western powers and anti-regime activists, who expressed hope that other high-ranking defections would follow.
The high-level defections could be a sign that Assad's tightly wrapped regime is unraveling, but it was too early to be certain. There have been thousands of defections in the past, mostly low-level army conscripts, but until now no one as senior as the general and the ambassador had fled.
In a statement broadcast on the Arabic satellite channel Al-Jazeera, Fares said he was resigning and joining the opposition. Wearing a dark suit and reading from a prepared text in what appeared to be a large office, Fares harshly criticized Assad.
"I'm announcing from this moment on that I'm siding with the revolution in Syria," he said, according to the Al-Jazeera translation into English. He called on all Syrians to abandon Assad.
"Where is the honor in killing your countrymen? Where is the national allegiance? The nation is all the people, not one person in particular," he said. "The allegiance is to the people, not to a dictator who kills his people."
It was not known where or when Fares recorded the statement.
Appointed to the Baghdad post four years ago, Fares was the first Syrian ambassador to Iraq in 26 years. Like Tlass, he is a member of the privileged Sunni elite in a regime dominated by Assad's minority Alawite sect.
Khaled Khoja, a member of the opposition Syrian National Council who is based in Istanbul, said Fares was "moving toward Turkey." Asked for details, Khoja said the information came from his own sources on the ground in Iraq.
There was no immediate comment from either Iraq or Syria. An operator who answered the phone at the Syrian Embassy in Baghdad said there was nobody at the embassy. When asked if the ambassador is currently in Iraq, the operator said he did not know.
White House spokesman Jay Carney said the U.S. had no confirmation of the defection as of Wednesday afternoon. But he said recent high-level defections from the Assad regime were "a welcome development."
"That is an indication of the fact that support for Assad is crumbling," Carney said.
State Department spokesman Patrick Ventrell said that if true, Fares would be the first senior diplomat from the regime to defect.
The conflict in Syria has defied every international attempt to bring peace. Although the Assad government's crackdown has turned the Syrian president into an international pariah, he still has the support of strong allies such as Russia, Iran and China.
A prominent Syrian opposition leader said Wednesday during a visit to Moscow that Russia's resistance to international intervention in the conflict was bringing misery and "suffering" to the violence-torn country.
Two Syrian opposition delegations visited Moscow this week, raising hopes that Russia could be pushed to accept the ouster of Assad. But Syrian National Council head Abdelbaset Sieda said he saw "no change" in Moscow's stance after meeting with officials including Foreign Minister Sergey Lavrov.
"The Syrian people are suffering because of Russia, because of the position it has taken, because of its veto in the U.N. Security Council," Sieda said at a news conference. "The current regime uses Russian weapons against its own people."
Activists estimate 17,000 people have been killed since the uprising began, and as the conflict continues, the rebellion appears to be getting more and more radicalized and violent, making any peaceful resolution or transfer of power a long-shot.
International envoy Kofi Annan urged the U.N. Security Council on Wednesday to send a message to the Syrian government and the opposition that there will be "consequences" if they don't comply with demands for an immediate cease-fire, a U.N. diplomat said.
Russia and China, veto-wielding council members, have blocked repeated attempts by the United States and its European allies to even threaten "consequences" — a diplomatic code word for sanctions.
The diplomat, speaking on condition of anonymity because Annan's videoconference briefing from Geneva was at a closed session, said the council should insist on implementation of its resolutions, which included a strong endorsement of his six-point peace plan.
That plan calls for an immediate cease-fire and withdrawal of heavy weapons from populated areas by the Syrian government, to be followed by an opposition cessation of hostilities.
The U.N. sent a 300-strong unarmed observer mission for 90 days to oversee the cease-fire and monitor implementation of the Annan plan. But it was forced to withdraw from key conflict areas because of escalating fighting and the council must decide what to do about extending its mandate, which expires on July 20.
Another U.N. diplomat said U.N. peacekeeping chief Herve Ladsous told the council the observers should remain and the U.N. should decide on their deployment. A third diplomat said the peacekeeping department plans to temporarily withdraw half of the 300-member mission, on 48-hour standby to return if conditions change.
They spoke on condition of anonymity because Annan spoke behind closed doors.
Annan also said Wednesday that Assad has discussed the possibility of forming a transitional Syrian government. An international conference in Geneva last month proposed having a transitional framework.
Annan said the Syrian leader during recent talks in Damascus "did offer a name" of someone who could serve as an interlocutor for the regime as it explores ways of forming a transitional government with the opposition. Annan, the U.N.-Arab League envoy to Syria, told reporters in Geneva that he was now considering the person whom Assad proposed, but he did not identify who it is.
He spoke Wednesday after a videoconference session with the U.N. Security Council in New York.
Also Wednesday, a Greek Orthodox priest said a group of Christians trapped in the besieged, bombed-out Syrian city of Homs has been evacuated after a deal between the army and rebels. The priest, Maximos al-Jamal, said 63 people were taken out to safety over the past 24 hours.
Christians, who make up about 10 percent of Syria's population, say they are particularly vulnerable to the violence sweeping the country of 22 million people. They are fearful that Syria will become another Iraq, with Christians caught in the crossfire between rival Muslim groups.
Homs, Syria's third-largest city, has a substantial Christian population and has been one of the hardest-hit regions during the uprising. Rebels control several neighborhoods, which has sparked several rounds of intense attacks by government troops over the past months.
Syrian Christians have largely stuck by Assad, fearing the strength of Islamist hard-liners in the uprising against his rule.
"I stayed inside Hamidiyeh to protect the churches from looting. I saved 14 icons from the St. George church which has been destroyed," said Jihad Akhras, who was among those who were evacuated Wednesday.
He said the situation inside Hamidiyeh and Bistan al-Diwan was "tragic" with barely enough food for those who remain trapped there.