Syria's new authorities under interim President Ahmed al-Sharaa have sought to disband armed groups
The Syrian Observatory for Human Rights war monitor has reported that 745 Alawite civilians were killed in Latakia and Tartus provinces.
Syrian authorities said the violence began when remnants loyal to Assad launched a deadly and well-planned attack on their forces on Thursday.
There were no immediate claim of responsibility for the attack.
Sharaa was appointed Wednesday to lead Syria for an unspecified transitional period
No group has claimed the four activists' abduction and they have not been heard from since.
Ankara-backed rebels played a key role in supporting Sharaa's Islamist group Hayat Tahrir al-Sham (HTS), which headed a rebel alliance that seized Damascus on December 8, toppling longtime ruler Bashar al-Assad.
The seismic change in Syria is expected to yield deeper Turkish sway just as a change of US administration is raising questions over how long Washington will keep backing the country's Kurdish-led forces.
Assad fled Syria following a lightning offensive spearheaded by the Islamist Hayat Tahrir al-Sham (HTS), more than 13 years after his crackdown on democracy protests precipitated one of the deadliest wars of the century.
Nigerian militant group Boko Haram pledges allegiance to Islamic State (IS) via Twitter post
The military chief of Syria's al-Nusra Front militant group is killed in an air strike, says the group
Melanie Smith monitors around 90 women daily who are believed to be living with Islamic State militants in Syria and Iraq and depicts an idea into what life really is like inside IS
A former Royal Marine became the first Briton to be killed while fighting alongside Kurdish forces against Islamic State in Syria, the Kurdish militia
Nineteen of 220 members of an Assyrian Christian community kidnapped by Islamic State (IS) in Syria released
The man identified as extremist "Jihadi John" said he felt like a "dead man walking" after being contacted by UK security services
CCTV pictures have emerged showing three UK schoolgirls on the Turkish leg of what is believed to have been their journey to join Islamic State in Syria
The masked Islamic State militant known as "Jihadi John", who has been pictured in the videos of the beheadings of Western hostages, has been named.
Fears are growing for the safety of three east London schoolgirls who police believes are trying to cross the Turkish-Syrian border to join Islamic State (IS).
President Barack Obama says US 'not at war with Islam - we are at war with people who have perverted Islam
