"Several sources in the village say at least 50 people were killed in summary executions and shelling in Bayda village," a southern suburb of the Alawite-majority city, Rami Abdel Rahman of the Syrian Observatory for Human Rights told AFP.
The official SANA news agency said troops killed "terrorists" -- the regime term for insurgents -- and seized arms in an operation targeting rebels.
Regular forces were supported by pro-regime "shabiha" militiamen, said the Observatory, which relies on a network of sources on the ground for its information.
The Banias region is predominantly Alawite, an offshoot of Shiite Islam and the sect of President Bashar al-Assad, while the insurgents battling to topple his regime are mainly Sunni Muslims.
On Friday, the army bombarded Sunni areas of Banias as heavy gunfire rocked southern parts of the city, the Observatory said.
Abdel Rahman said troops were raiding homes and making arrests.
"I fear that there could be a massacre like the one that happened yesterday in Bayda."
France denounced the bloodshed in Banias.
"France is outraged by the massacres carried out against the Sunni population of the port city of Banias," foreign ministry spokesman Philippe Lalliot said in Paris.
"These crimes should not go unpunished. Those who carried them out should stand accountable before international criminal justice," he said.
Elsewhere, rebels fired two rockets at Damascus international airport, hitting an aircraft and a fuel dump and sparking a massive fire, SANA said.
"One rocket hit a kerosene tank and the other hit a parked commercial aircraft, badly damaging it," SANA said, adding traffic was "normal" and the fire had been extinguished.
Rebels have claimed several times to have fired at Damascus airport but it was the first such report from the official media.
The latest violence also took its toll on Good Friday and many Syrian Greek Orthodox did not expect churches to be full for the solemn prayers marking the crucifixion of Christ. "I don't dare to go to church tonight," said Shaza.
With the Syrian conflict that has cost more than 70,000 lives now in its third year, the United States said Thursday it was taking a fresh look at whether to arm the outgunned rebels.
After having rejected the idea previously, President Barack Obama's deputies were weighing the option of providing weapons to the rebels, Defence Secretary Chuck Hagel told reporters.
Asked whether Washington was rethinking its opposition to arming the rebels, Hagel replied with a firm "Yes." But he said no decision had been reached.
Obama said Hagel's comments represented the view he has expressed for "months".
"As we've seen evidence of further bloodshed, potential use of chemical weapons inside of Syria, what I've said is that we're going to look at all options," he said in Mexico.
But, Obama added, "we want to make sure that we look before we leap and that what we're doing is actually helpful to the situation, as opposed to making it more deadly or more complex."
Speculation has mounted that the Obama administration could reverse its opposition to arming the rebels after officials said last week that US spy agencies now believe Syria's regime may have used chemical weapons on a small scale.
But experts have said a military mission to secure the chemical weapons would require a large ground force and pose huge risks, with the outcome hinging on the quality of Western intelligence.
Meanwhile, the family of a US journalist missing in Syria said he is believed to be in the hands of government intelligence agents at a detention centre near Damascus.
James Foley, a 39-year-old freelancer who has filed reports for GlobalPost, Agence France-Presse and other outlets, has been missing in Syria for nearly six months.
"With a high degree of confidence, we now believe that Jim was most likely abducted by a pro-regime militia group, commonly referred to as the shabiha, and subsequently turned over to Syrian government forces," said GlobalPost chief Phil Balboni.