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.
The flow of migrants through the Balkans picks up again with thousands entering Croatia, and the number doubling in a day for Germany.
The Australian government has confirmed it has launched its first air strikes inside Syria against targets of the so-called Islamic State (IS).
Hungarian riot police fire tear gas and water cannon to force back migrants who broke through gates at the now closed Serbia-Hungary border.
Hundreds of migrants are stranded at the Serbia-Hungary border after the Hungarian government closed the frontier with a new razor-wire fence.
Russia's recent movements near Syria's city of Latakia suggest that Moscow plans to establish a "forward air operating base" there, the US has said.
Jumaa Ibrahim and his wife Hasnaa Karam, a Syrian couple in their early 60s, arrived in Mecca on Friday, and headed straight to Islam's holiest site, the cube-shaped Kaaba.
Ending the conflict in Syria and Iraq is key to solving the migrant crisis facing Europe, a senior US official tells the BBC.
Germany is to introduce some form of border controls with Austria, German and Austrian media report, as thousands more migrants arrive this weekend.
The number of migrants entering Hungary from Serbia hit a new record on amid tension in eastern Europe over how to deal with the crisis.
Two Russian cargo planes carrying 80 tonnes of humanitarian aid have landed in Syria, Syrian state media say.
