(AFP) - The death toll from the sinking of a boat carrying migrants from Madagascar to the French Indian Ocean island of Mayotte has risen to 34, authorities said on Tuesday.

The boat, which was carrying about 60 passengers, sank off the island's northern coast on Saturday night.

Initial reports on Monday put the death toll at just over 20.

Bodies recovered by the authorities on Tuesday, including those of three children, were "in an advanced state of decomposition", Jean Edmond Randrianantenaina, director of the Port, Maritime and River Agency (APMF) told AFP.

An investigation is underway.

All but one of the 24 survivors rescued Saturday night by fishermen reportedly fled before the authorities arrived, and that was a young pregnant woman.

According to a source at the gendarmerie, the boat capsized due to overloading.

The APMF had in a statement Monday that the dead had "clandestinely taken a boat headed to Mayotte, but that sank".

Investigators want to track down the smugglers, who are suspected to be among the survivors on the run, and establish how they operated.

Many migrants try each year to reach the French territory of Mayotte, which lies north of Madagascar in the Indian Ocean.

In 2021, more than 6,500 people were detained trying to enter the territory clandestinely, according to French authorities.

There are no reliable statistics on how many people have lost their lives attempting such crossings. A French senate report published in the early 2000s estimated that around 1,000 people were dying each year.

© Agence France-Presse