Dozens of Syrians staged a rare protest in the coastal city of Latakia, bastion of President Bashar al-Assad, calling for the punishment of a member of his family they accuse of killing an army officer over a traffic dispute, monitors said.

The Britain-based Syrian Observatory for Human Rights said more than 1,000 people gathered in Latakia on Saturday night holding up pictures of Colonel Hassan al-Shaikh, who died after a traffic incident there last week.

The demonstrators called for the execution of Suleiman al-Assad, son of the president's cousin Hilal, who was killed in battles with Islamist insurgents last year. They also chanted slogans in support of the president.

Details of what happened vary. But according to the Observatory and supporters of President Assad on social media, Suleiman al-Assad was angered when al-Shaikh, who was in a car with his family, overtook his vehicle in a Latakia street, and so shot him dead nearby shortly afterwards.

Some Assad supporters said Suleiman's bodyguard was the one who killed al-Shaikh.

In a video posted on social media, protesters chanted: "The people want the execution of Suleiman."

There were no reports of clashes between protesters and police in Latakia. Syria's state media did not report the protest, the traffic incident or the reported killing.

In Syria's continuing civil war, Alawites who make up roughly 10 percent of the 23 million population, have largely backed Assad against mainly Sunni Muslim insurgents.

But opposition activists say dissent has been growing within Assad's Latakia regional heartland largely due to the high death toll of Alawite fighters and civilians -- tens of thousands -- in the conflict, as well as official corruption.