Syria's deputy oil minister has announced his defection in an online video, making him the highest ranking official to abandon President Bashar Assad's regime since the country's uprising erupted a year ago.
Abdo Husameddine said he was defecting because of the "brutal" crackdown on dissent which has claimed the life of thousands of Syrians in the past year.
There has been a steady stream of army defections who have joined a group of dissidents known as the Free Syrian Army, now numbering in the thousands, but civilian government officials have remained largely loyal to Assad's regime.
In the video posted on YouTube, Husameddine identified himself as an "assistant" to the oil minister and a member of the ruling Baath Party. Ministers in Syria may have several assistants known as deputies. He is shown wearing a suit and tie and sitting on a sofa, reading from a paper.
"I, Abdo Husameddine, deputy oil and mineral resources minister, announce my defection from the regime and resignation from my post ... and declare that I am joining the dignified people's revolution," he said.
He appeared to address Assad directly. "You have inflicted on those you claim are your people a full year of sorrow and sadness, denied them the their basic rights to life and humanity and pushed the country to the edge of the abyss," he said.
"I do not want to end my life servicing the crimes of this regime," said Husameddine, adding that he has served 33 years in various government positions.
It was not clear when or where the video was filmed, and there was no immediate comment from Damascus.
There have been numerous military defections recently, including Syrian brigadier-general Mostafa Ahmad al-Sheik who fled to Turkey in January, becoming the highest-ranking officer to defect.
In late August, Adnan Bakkour, the attorney general of the central city of Hama, appeared in a video announcing he had defected from the regime. Authorities reported he had been kidnapped and said he was being kept against his will by gunmen. He has not been heard of since.
Husameddine said he was defecting "knowing full well that this regime will burn my home, persecute my family and make up a lot of lies."
"I advise my colleagues ... to abandon this sinking ship," he added.
The UN says more than 7,500 people have been killed since Syria's uprising began. Activists put the death toll at more than 8,000.
The defection comes following a month-long assault by government forces on the rebellious district of Baba Amr in the central city of Homs that brought international condemnation. A key stronghold of the uprising against Assad, it was wrested from rebel control on March 1.
Activists accused the government of trying to cover up evidence of atrocities there.
The UN humanitarian chief Baroness Valerie Amos was allowed a brief tour in Baba Amr on Wednesday, becoming the first independent outside observer to be allowed in since the military overran the district. She said she found most residents of the ravaged neighbourhood had fled following the bloody military siege.
In Cairo, former UN Secretary-General Kofi Annan who has been appointed the new special envoy to Syria met the Arab League chief and the Egyptian foreign minister today.
Annan is scheduled to travel to Damascus on Saturday where he is likely to meet Assad.