The Syrian health ministry said at least 461 people were killed and 1,326 others injured in the country after powerful earthquakes hit Syria and Türkiye early on Monday.
The ministry's casualties, however, do not cover the rebel-held parts of Idlib Province and the countryside of Aleppo Province.
The Syrian Observatory for Human Rights, a Britain-based pro-rebel watchdog, said 409 people were killed by the earthquake in the two areas mentioned above.
In the central province of Hama, rescue work has been going on to secure shelters for those who lost their homes following the massive earthquakes, Interior Minister Mohammad Khaled al-Rahmoun told Xinhua at the site of a collapsed building in the al-Arabeen neighborhood in the province.
In front of a seven-storey building in Hama, which was home to 100-150 people, the coordinator of the emergency unit at the Syrian Arab Red Crescent (SARC) Alaa Shaker said only 45 of them have so far been rescued.
"We have reports on deaths between 15 and 20 people under the building," he added.
The Syrian government has set up a 24-hour central operation center to coordinate earthquake relief operations, with all relevant ministries, institutions and authorities on alert, state news agency SANA reported.
The central operation center was led by Syrian Prime Minister Hussein Arnous.
Powerful earthquakes rocked southern Türkiye and its neighbor Syria early Monday, killing at least 1,498 and injuring 8,533 in Türkiye so far, according to statistics released by Türkiye's Disaster and Emergency Management Authority.