Syria's new rebel-led authorities say 14 interior ministry personnel have been killed and 10 injured in an "ambush" by forces loyal to ousted President Bashar al-Assad in the west of the country.

They say the fighting took place near the Mediterranean port of Tartous on Tuesday.

Reports say the security forces were ambushed as they tried to arrest a former officer in connection to his role at the notorious Saydnaya prison, close to the capital Damascus.

Just over two weeks ago, Assad's presidency fell to rebel forces led by the Islamist Hayat Tahrir al-Sham (HTS) faction.

The UK-based Syrian Observatory for Human Rights (SOHR) said three militants were also killed in the clashes.

The SOHR added that the security forces later brought in reinforcements.

In a separate development, the Syrian authorities imposed an overnight curfew in the central city of Homs, state media reported.

Reports say this followed unrest after a video purportedly showing an attack on an Alawite shrine.

Syria's interior ministry said it was an old video, dating back to the rebel offensive on Aleppo in late November, and the violence was carried out by unknown groups.

The SOHR said one demonstrator was killed and five wounded in Homs.

Demonstrations were also reported in areas including the cities of Tartous and Latakia, and Assad's hometown of Qardaha.

Alawites are the minority sect from which the Assad family originates, and to which many of the former regime's political and military elite belonged.

The HTS-led lightning offensive that started from Syria's north-east and spread all over the country ended the Assad family's more than 50-year-rule.

HTS has since promised to protect the rights and freedoms of many religious and ethnic minorities in Syria.

HTS is designated as a terrorist organisation by the UN, the US, the EU, the UK and others.

On Tuesday, protests broke out in the country over the burning of a Christmas tree, prompting fresh calls for the new authorities to protect minorities. (BBC)