The secretary general of the Kurdish Progressive Democratic Party, Abd al-Aziz Dawud, also said security officials had threatened even harsher measures in a meeting with Kurdish leaders.
"Instead of calming things down and showing themselves to be more flexible, Syrian security officers have threatened to take repressive measures and arrest more people," Dawud said in a statement.
The statement followed a meeting between Kurdish leaders and the security services on Saturday in Hassake, more than 500km north of Damascus.
"These security officials issued these threats knowing full well that the number of detained Kurds has passed 2000," he said.
Authorities informed the Kurds last week of the release of around 600 of their people, but Dawud said at the time that another 1500 were still detained in Hassake and Aleppo provinces where the clashes took place.
Kurdish leaders said 40 people were killed in the six days of clashes which broke out on 12 March. An official toll put the number of dead at 25.
"Instead of calming things down and showing themselves to be more flexible, Syrian security officers have threatened to take repressive measures and arrest more people"
Abd al-Aziz Dawud,
Secretary general, Kurdish Progressive Democratic Party
The trouble broke out at a football match in Qamishli, 600km north of Damascus, when Arab tribesmen taunted Kurds with slogans against Iraqi Kurdish leaders and brandished portraits of deposed Iraqi dictator Saddam Hussein.
Syrian officials have accused foreign infiltrators of being behind the unrest, but Dawud cited growing resentment, including discrimination against Kurds in universities and the military.
The roughly 1.5 million Kurds in Syria make up about nine percent of the population, and live mostly in the north.