General Mohammed Khalluf, logistics chief of the Syrian national army, has defected, an activist video posted online reported.
Saturday's YouTube video, which could not be independently verified, shows a man with white hair in civilian clothes getting into a car and a voice offscreen naming him as General Mohammed Khalluf, head of logistics.
"A long time ago we started preparations to separate ourselves off from the Assad regime, in coordination with
rebel factions, until we succeeded today," the man said to be Khalluf, said in the video.
There was no comment about the defection on Syrian state news outlets.
The man speaking in the video says that Khalluf and his family were being escorted out of Syria on Friday.
Activists said they waited before reporting the defection to ensure that Khalluf and his family had crossed safely into neighbouring Jordan.
Elsewhere in the country, around 20 soldiers fled their posts for opposition territory near the ancient desert city
of Palmyra, according to the Syrian Observatory for Human Rights.
The British-based group, which has a network of activists across Syria, said the soldiers fled to farmlands near the city, where there has been shelling and gun battles for two days.
Since the March 2011 start of the conflict between the government of Bashar al-Assad and the armed opposition, dozens of senior army officers including some 40 generals have defected and headed to Turkey.
Turkish authorities have refused to give the exact number of Syrian defectors, who typically join the anti-Assad Free Syrian Army.
Riad Hijab, former prime minister, defected to Jordan in August 2012.