A Syrian military operation against remnants of the former Assad regime has now ended, having sparked some of the worst violence seen in the country in years.

Syria's fragile transition from decades of Assad family brutal rule has been greatly shaken with an outburst of sectarian retribution and killings, posing a serious challenge to the new leadership led by Ahmad Sharaa.

"To be honest, the Alawites clearly ask for international protection," a former Syrian diplomat told Newsweek.

A monitoring group says 973 civilians have been killed in revenge attacks against the Alawite sect since Thursday.

Hundreds of people were killed in Syria over four days after violent clashes between the army and loyalists of the deposed president Bashar al-Assad swept its western coastal region.

Syria's new authorities announced on Monday the end of an operation against loyalists of deposed president Bashar al-Assad, after nearly 1,000 civilians were killed in the worst violence since his overthrow.