At least five people have been killed in fresh clashes between Kurds and police in northern Syria, reports say.
Trouble was first reported after a brawl at a football match on Friday
A Kurdish politician told the Associated Press that two Kurds and three police officers were killed on Tuesday in a riot in Aleppo.
Several deaths have been reported in clashes between Arabs and the Kurdish minority over the past few days, but Syria denies any political unrest.
Syria has about two million Kurds among its population of 17 million.
There was no immediate confirmation of the deaths from the Syrian Government, which has not issued any figures for casualties since clashes between Kurds and Arabs began on Friday.
Witnesses told AP that a second riot in Afrin, 65 kilometres (40 miles) north of Aleppo, led to the death of two other people.
Another Kurdish source, Mashaal Timo of the Kurdish People's Union, told the French news agency AFP that that nine Kurds had been killed in overnight clashes with Arab residents in Aleppo.
The first violence came after a brawl at a soccer match
last Friday in Qameshli near the border with Turkey and Iraq.
At least nine people were killed and a railway station, schools and public offices were badly damaged.
The clashes have triggered a wave of protests among Syrian Kurds living in exile. They claim the authorities have encouraged violence against the Kurdish minority in the disturbances.
On Tuesday, Turkey's Anatolia news agency said security forces opened fire on Kurds marking the anniversary of the 1988 gas attack on Iraqi Kurds in the town of Halabja.
It said three people were shot dead in Aleppo and four in Afrin.