"A suicide bomber in a vehicle targeted the Asayish's local headquarters in Qamishli. There are at least 10 dead," said Rami Abdel Rahman, head of the so-called Syrian Observatory for Human Rights, AFP reported.
No group has claimed responsibility for the bombing yet, but the attack bore the hallmarks of the Takfiri militants operating in the Arab country.
Syria has been grappling with deadly foreign-backed militancy fueled by Takfiri groups since March 2011. More than 222,000 people have so far been killed in the crisis.
Over 3.8 million Syrians have also fled the violence to other countries, and more than 7.2 million others have become internally displaced, according to the United Nations.