BEIRUT - Syria's deputy oil minister defected and posted his parting words to President Bashar Assad in a video on YouTube Thursday, calling the regime criminal and urging his colleagues to also abandon the "sinking ship."

Abdo Husameddine's defection came at the height of international pressure against Assad's regime as it tries to suppress an uprising now morphing into an armed insurgency, with the U.S. considering options for military intervention.

The deputy minister is the highest ranking civilian official to abandon the regime since the revolt against Assad's iron-fisted rule began a year ago.

"I don't wish to end my life servicing the crimes of this regime," Husameddine said in the video, dressed in a suit and tie and apparently reading from a piece of paper. "This is why I have chosen to join the voice of righteousness, knowing that this regime will burn my home, persecute my family and come up with a lot of lies. I advise my colleagues who have been silent in the face of crimes for a year to abandon this sinking ship which is about to drown."

It was not clear when or where the video was made and he did not disclose his current location. There was no comment from the regime in Damascus.

"I declare that I am joining the revolution of the dignified people," Husameddine said.

"You have inflicted on those you claim are your people a full year of sorrow and sadness, and denied them their basic rights to life and humanity and pushed the country to the edge of the abyss with your intransigence and detachment from reality. The economy of the country has reached near collapse," he added.

Husameddine identified himself as an engineer and assistant to the oil minister. He said he was member of the ruling Baath Party, but was now quitting, and added he had served 33 years in various government positions. Cabinet ministers in Syria may have several assistants known as deputies.

Assad's regime has suffered a steady stream of army defectors, 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.

That made Husameddine's defection all the more rare.

Among numerous military defections recently was that of Brig. Gen. Mostafa Ahmad al-Sheik, who fled to Turkey in January, becoming the highest ranking officer to bolt. In late August, Adnan Bakkour, the attorney general of the central city of Hama, appeared in a 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 from since.

International pressure on Assad reached a new peak Wednesday when a senior U.S. military commander said President Barak Obama was assessing options for military intervention in Syria.

Although there are widespread concerns that military action could cause a regional upheaval in the Middle East, Army Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, told the U.S. Senate Foreign Relations Committee that Obama has ordered up a Pentagon review of options.

Dempsey said the options to be examined include enforcing a no-fly zone and humanitarian airlifts. He added that the military would study the situation and report back on points like Syria's sophisticated air defences and its extensive stockpile of chemical weapons.

The U.N. says more than 7,500 people have been killed in the year since the uprising began. Activists put the death toll at more than 8,000.

On Wednesday, the U.N. humanitarian chief, Valerie Amos, got the first independent outside look at the Baba Amr district of Homs following a deadly monthlong siege. The military took control of Baba Amr on March 1, but Amos was allowed in only Wednesday.

She said Thursday she was struck by the devastation she saw in the shattered neighbourhood. She found it mostly empty after residents fled the fighting. Activists charge that Syrian forces conducted cleanup operations there, including executions and arrests.

"The devastation there is significant. That part of Homs is completely destroyed, and I am concerned to learn what happened to the people in that part of the city," she said in the capital Damascus, a relatively peaceful stronghold of Assad's regime.

"I have been struck by the difference between what I have seen here in Damascus and what I saw yesterday in Baba Amr," she added.

But shortly after she spoke, Syrian security forces opened fire to disperse mourners in Mazzeh, an upscale neighbourhood of Damascus. The crowd had gathered for the funeral of a soldier who was allegedly executed last month for refusing to obey orders to shoot at civilians in Homs.

The British-based Syrian Observatory for Human Rights said scores of people were arrested as security forces attacked the crowd in Mazzeh. There was no word of casualties.

In Cairo, former U.N. chief Kofi Annan said his top priority as special envoy to Syria is to end the violence and deliver badly needed aid. He warned against further militarization of the conflict and urged the opposition to come together with the government to find a political solution.

"I hope that no one is thinking very seriously of using force in this situation," Annan said. "I believe any further militarization would make the situation worse."

Addressing a news conference after talks with Arab League chief Nabil Elaraby, he said he would be making "realistic" proposals to resolve the conflict. He did not elaborate.

Annan, who has been appointed joint U.N.-Arab League envoy to Syria, is scheduled to travel to Damascus on Saturday, where he will likely meet Assad. He said his mission was to start a "political process" in Syria to resolve the conflict there, and his only priority was the welfare of the Syrian people. "They are a brave, ancient people and they deserve better," he said.