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.
More than 50 State Department diplomats signs an internal memo sharply critical of US policy in Syria, calling for military strikes against President Bashar al-Assad's government to stop its persistent violations of a cease-fire in the country's civil war.
Mouhamad, a 40-year-old dentist and poet, lived in Aleppo, Syria, for many years.
Terrorist attacks and the total number of deaths increased in Bangladesh in 2015, according to the US State Department.
The US, UK and France urge the UN to begin air drops of humanitarian aid to besieged areas in Syria.
The chief negotiator of Syria's main opposition umbrella group, Mohammed Alloush, has resigned over what he called the failure of peace talks.
Islamic State fighters capture territory from Syrian rebels near the Turkish border and inch closer to a town on a supply route for foreign-backed insurgents fighting the jihadists, a monitoring group said.
New satellite imagery appears to reveal extensive damage to a strategically significant airbase in central Syria used by Russian forces after an attack by so-called Islamic State (IS).
Islamic State (IS) is losing territory, its finances are being drained and the number of foreign fighters recruited has reportedly down to a trickle, dropped by as much as 90 percent from a high of 2,000 a month in the past year.
The Syrian government has accused Turkey, Qatar and Saudi Arabia of being behind a wave of bombings in the coastal cities of Tartous and Jableh.
Bomb blasts kill scores of people in Jableh and Tartous on Syria's Mediterranean coast with many others wounded in the government-controlled territory that hosts Russian military bases, monitors and state media said.
