The death toll from two days of clashes between security forces and loyalists of ousted Syrian President Bashar al-Assad and revenge killings that followed has risen to more than 600, a war monitoring group said Saturday, making it one of the deadliest acts of violence since Syria’s conflict began 14 years ago.

The clashes, which erupted Thursday, marked a major escalation in the challenge to the new government in Damascus, three months after insurgents took authority after removing Assad from power.

The government has said it was responding to attacks from remnants of Assad's forces and blamed “individual actions” for the rampant violence.

Retribution killings

The revenge killings that started Friday by Sunni Muslim gunmen loyal to the government against members of Assad’s minority Alawite sect are a major blow to Hayat Tahrir al-Sham, the faction that led the overthrow of the former government. Alawites made up a large part of Assad’s support base for decades.

Residents of Alawite villages and towns spoke to The Associated Press about killings during which gunmen shot Alawites, most of them men, in the streets or at the gates of their homes. Many homes of Alawites were looted and then set on fire in different areas, two residents of Syria’s coastal region told the AP from their hideouts.

They asked that their names not be made public out of fear of being killed, adding that thousands of people have fled to nearby mountains for safety.

Atrocities in one town

Residents of Baniyas, one of the towns worst hit by the violence, said bodies were strewn on the streets or left unburied in homes and on the roofs of buildings, and nobody was able to collect them. One resident said that the gunmen prevented residents for hours from removing the bodies of five of their neighbors killed Friday at close range.

Ali Sheha, a 57-year-old resident of Baniyas who fled with his family and neighbors hours after the violence broke out Friday, said that at least 20 of his neighbors and colleagues in one neighborhood where Alawites lived were killed in their shops or homes.

Sheha called the attacks “revenge killings” of the Alawite minority for the crimes committed by Assad's government. Other residents said the gunmen included foreign fighters and militants from neighboring villages and towns.

“It was very, very bad. Bodies were on the streets,” Sheha said as he was fleeing, speaking by phone nearly 20 kilometers from the city.

He said the gunmen were gathering less than 100 meters from his apartment building, firing randomly at homes and residents and, in at least one incident he knows of, asked residents for their IDs to check their religion and their sect before killing them. He said the gunmen also burned some homes and stole cars and robbed homes.

Death toll triples

The Britain-based Syrian Observatory for Human Rights, a war monitor, said that 428 Alawites have been killed in revenge attacks in addition to 120 pro-Assad fighters and 89 from security forces. Observatory chief Rami Abdurrahman said that revenge killings stopped early Saturday.

“This was one of the biggest massacres during the Syrian conflict,” Abdurrahman said about the killings of Alawite civilians.

The previous figure given by the group was more than 200 dead. No official figures have been released.

A funeral was held Saturday afternoon for four Syrian security force members in the northwestern village of Al-Janoudiya after they were killed in the clashes along Syria's coast. Scores of people attended the funeral.

Syrian forces surging

Syria’s state news agency quoted an unnamed Defense Ministry official as saying that government forces have regained control of much of the areas from Assad loyalists. It added that authorities have closed all roads leading to the coastal region “to prevent violations and gradually restore stability.”

On Saturday morning, the bodies of 31 people killed in revenge attacks the day before in the central village of Tuwaym were laid to rest in a mass grave, residents said. Those killed included nine children and four women, the residents said, sending the AP photos of the bodies draped in white cloth as they were lined in the mass grave.

Lebanese legislator Haidar Nasser, who holds one of the two seats allocated to the Alawite sect in parliament, said that people were fleeing from Syria for safety in Lebanon. He said he didn't have exact numbers.

Nasser said that many people were sheltering at the Russian air base in Hmeimim, Syria, adding that the international community should protect Alawites who are Syrian citizens loyal to their country. He said that since Assad’s fall, many Alawites were fired from their jobs and some former soldiers who reconciled with the new authorities were killed.

Under Assad, Alawites held top posts in the army and security agencies. The new government has blamed his loyalists for attacks against the country’s new security forces over the past several weeks.

The most recent clashes started when government forces tried to detain a wanted person near the coastal city of Jableh and were ambushed by Assad loyalists, according to the Observatory.