At least 73 people died from a boat that sank off the Syrian coast on Thursday, the Syrian Health Ministry said Friday.

Twenty others have been rescued and sent for medical treatment at the al-Basel hospital in the Syrian coastal city of Tartous after the boat sank in the Syrian waters, Health Minister Hassan al-Ghabbash said in a statement.

The boat set off from Lebanon on Tuesday carrying illegal migrants of various nationalities to "unknown destinations," Syrian General Director of Sea Ports Samer Kobrosly earlier said, citing testimonies from the survivors.

The latest casualties included 31 bodies found on Friday during an ongoing search and rescue mission launched by Syrian authorities, Kobrosly added.

Head of the Syrian Observatory for Human Rights Rami Abdul-Rahman cited sources as saying on Friday that the boat carried between 100 to 150 people, noting that the original capacity of the boat was only enough for 30 people.

Lebanese, Syrians and other unidentified nationalities were on the boat, the Britain-based war monitor revealed on Thursday, adding that the migrants' initial destination was Cyprus.

According to Lebanese Public Works and Transport Minister Ali Hamieh, the 20 rescued migrants are five Lebanese, 12 Syrians, and three Palestinians.

Hamieh said in a statement that the Lebanese Red Cross is coordinating with the Syrian Red Crescent on bringing some of the victims' bodies home.