Damascus (AFP) - A Syria war monitor said Friday that security forces killed 136 members of the Alawite minority, to which toppled president Bashar al-Assad belongs, a day after deadly clashes with gunmen loyal to him triggered a major security operation.

The Syrian Observatory for Human Rights said at least 231 people have been killed since the clashes erupted on Thursday along the country’s western coast.

They were the fiercest attacks on Syria’s new rulers since Assad’s ouster, and followed other deadly incidents in the area earlier this week.

Restoring security has been one of the most complex tasks for Syria’s new authorities, installed after Islamist-led forces ousted Assad in a lightning offensive in December.

Western powers and Syria’s neighbours have emphasised the need for unity in the new Syria, which is seeking funds for reconstructing a nation ravaged by years of war under Assad.

The Britain-based Observatory said the 136 dead civilians, including at least 13 women and five children, “were executed by security forces in the regions of Banyas, Latakia and Jableh.”

The Observatory and activists released footage showing dozens of bodies in civilian clothing piled in the yard of a house, with blood stains nearby and women wailing.

Other videos appeared to show men in military garb shooting people at close range.

AFP could not independently verify the images.

The United Nations envoy for Syria, Geir Pedersen, decried “very troubling reports of civilian casualties”.

He called on all sides to refrain from actions which could “destabilise Syria, and jeopardise a credible and inclusive political transition.”

An interior ministry source quoted by official news agency SANA said isolated incidents had occurred on the coast and pledged to put a stop to them.

“After remnants of the toppled regime assassinated a number of security personnel, popular unorganised masses headed to the coast, which led to a number of individual violations,” the source said.

After Thursday’s clashes, which according to the Observatory left 78 dead – about half security force members and the other half gunmen, plus seven civilians – the authorities had launched a sweeping security operation.

Mustafa Kneifati, a security official in Latakia, said that in “a well-planned and premeditated attack, several groups of Assad militia remnants attacked our positions and checkpoints, targeting many of our patrols” around the coastal town of Jableh.

- Curfews -

A curfew was imposed until Saturday in the coastal provinces of Latakia and Tartus, heartland of the ousted president’s Alawite religious minority, and authorities on Friday announced a security sweep in the Jableh area, between Latakia and Tartus.

Officials blamed “sabotage” for a power outage that affected much of Latakia province.

A curfew has also been imposed in Syria’s confessionally divided third city Homs.

The security operation “targeted remnants of Assad’s militias and those who supported them”, an official cited by SANA said, as he called on civilians to “stay in their homes”.

On Friday SANA said a security operation was launched in Assad’s hometown of Qardaha, near Latakia, “against loyalists of the former regime.”

SANA said that during their operation, security forces detained Ibrahim Huweija, a general who was “accused of hundreds of assassinations” under Assad’s father and predecessor, Hafez al-Assad.

Ali, a farmer living in Jableh, told AFP he saw “urban battles and street fighting”.

“All night, we heard the sounds of gunfire and explosions,” he said.

“Everyone’s afraid… we are trapped at home and we can’t go out.”

- ‘Under attack’ -

Thursday’s clashes saw security forces conduct helicopter strikes after they clashed with gunmen loyal to Assad-era special forces commander Suhail al-Hassan in the village of Beit Ana.

Earlier in the week the Observatory had reported four civilians killed in a security operation in the Latakia area, where state media had said “militia remnants” supporting Assad killed two security personnel in an ambush.

“Both sides feel like they’re under attack, both sides have suffered horrific abuses at the hands of the other side, and both sides are armed,” Syria expert Aron Lund, a fellow at the Century International think tank, told AFP.

Forces led by Islamist group Hayat Tahrir al-Sham launched the offensive that toppled Assad on December 8, when he fled to Russia with his family.

Syria’s new security forces have since carried out extensive campaigns seeking to root out Assad loyalists from his former bastions.

During those campaigns, residents and organisations have reported executions and other violations, which the authorities have described as “isolated incidents”.

Russia, Assad’s main backer that helped turn the tide of the war in his favour before he was toppled, called on Syrian authorities to “do their utmost to put an end to the bloodshed as soon as possible”.

The foreign ministry of Iran, another major ally of Assad, said it strongly opposes “harming innocent Syrian people from any group and tribe, and considers it to be paving the ground for the spread of instability in the region.”

Saudi Arabia and Turkey reaffirmed their support for the new authorities, while Jordan condemned “attempts to drive Syria toward anarchy”.