"Terrorists detonated a car laden with many explosives at noon (1430 IST) in Hamam square in Latakia, killing 10 people," the official SANA news agency reported.
It said the explosion had also wounded 25 people and caused significant damage to nearby cars and buildings.
State television aired footage of charred cars with their windows blown out, and firefighters attempting to put out blazes in the city.
Latakia, the heartland of the minority Alawite sect to which the Assad clan belongs, has been largely spared the violence that has wracked Syria since an uprising against its rule erupted in March 2011.
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The Syrian Observatory for Human Rights called today's explosion "the biggest car bomb attack in Latakia since the war began."
"This is rare for Latakia city, which is usually hit by rockets," Observatory head Rami Abdel Rahman told AFP.
Rebels entrenched in the hilly terrain around Latakia regularly fire rockets and other missiles into the city.
Abdel Rahman said the car bomb detonated on the northern edges of the city and "wounded dozens, including four or five in critical condition."
Many Syrians displaced by violence in neighbouring regions have taken refuge in Latakia province and some businesses have moved to the relative safety of the area.
More than 240,000 people have been killed in the conflict, which has spiralled from an anti-government movement to a multi-front civil war.