At least 14 people were killed in northeastern Syria on Friday and Saturday in riots which began with brawling in a soccer match in the town of Kameshli, near the border with Turkey.
An official statement late on Saturday warned that law violators would face "the severest punishments" and Interior Minister Ali Haj Hammud travelled to the Kameshli area to take charge of efforts to end the disturbances, in which buildings were damaged in several towns and up to 40 people badly injured.
Sporadic gunfire could be heard in Kameshli on Sunday, and movement was heavily restricted.
Security officers and residents armed with licensed hunting rifles roamed the streets of the city, where public and private institutions were vandalised on Saturday. They said their orders were not to use force unless "absolutely necessary".
Public offices in al-Hassaka governorate, which has a population of 1.5 million, were open for business, but parents were keeping their children away from school, officials and residents said. Syrian Kurds make up 12% of the population of the governorate.
Khalid Khidir, deputy governor of al-Hassaka, accused Kurdish political groupings of instigating the rioting.
"The parties that instigated (the violence), which have internal and external affiliations, have deployed some poor Kurds to use them and exploit them in what happened," he said.
Kurdish groups and some human rights bodies, in a joint statement made available to Reuters in Beirut, accused the state of "neglecting the rights of Kurdish citizens" and urged self-restraint to contain the situation.
The riots came as the Bush administration moved closer to imposing sanctions on Damascus to punish it for its foreign policies, including its refusal to close down Lebanese and Palestinian guerrilla groups which attack Israelis.
The newspaper al-Baath, mouthpiece of the ruling Arab Baath Socialist Party, said in an editorial on Sunday the unrest had been orchestrated "under a plan intended to harm Syria and contribute to the sum of well-known pressures on Syria".
Sources close to government thinking said some Kurdish politicians had tried to turn the issue "from a soccer match riot into an issue of a political dimension," a reference to the grievances of about 200,000 Syrian Kurds not recognised as citizens.
One of the sources said the government was close to announcing a solution to the problem of the stateless Kurds, but propaganda by banned Kurdish groups had held back the process.
Kurds make up two million of Syria's 17 million population, but Syrian officials avoid reference to Kurds as a distinct minority and stress the importance of national unity.
Kurds and members of other minorities in Syria have held senior government and army positions.