The killings followed clashes sparked by the arrest of a wanted suspect in a predominantly Alawite village, the Observatory reported.
The monitor said there had been a "relative return to calm" in the region on Saturday, as the security forces deployed reinforcements.
A defence ministry source told SANA that troops had blocked roads leading to the coast to prevent "violations", without specifying who was committing them.
Latakia province security director Mustafa Kneifati told the news agency: "We will not allow for sedition or the targeting of any component of the Syrian people."