Libyan authorities have recovered the bodies of 100 migrants trying to reach Europe who drowned after their boat sank off Libya, officials said on Wednesday.

"Seventy seven bodies of the migrants washed up in the beach west of Tripoli late on Tuesday and 23 more bodies were found between Sunday night and Tuesday," an official told Reuters.

He and other officials believed the migrants were among 365 people who boarded the ship, which was supposed to hold only 75 people.

The migrants were Somalis, Nigerians, Eritreans, Kurds, Algerians, Moroccans, Palestinians and Tunisians, officials said. The ship was one of four migrant boats which had sailed from Libya between Saturday and Sunday, apparently heading to Italy, Libyan officials said.

Libyan coastguards had rescued 350 migrants, many of them women and children, after their boat broke down on Sunday near a Libyan offshore oilfield. they said.

"As for the fate of the two remaining boats, we have information that one had reached Italy and the latest information we had about the other boat was it had left Libyan waters and was spotted close to Malta," a Libyan official said.(An AFM spokesman said the boat had been offshore Malta but had continued on its journey towards Italy)

There are an estimated 1 to 1.5 million African migrants in Libya, drawn by the need for unskilled labour, according to International Organisation for Migration (IOM).

Libya is both a transit and a destination country for migrants. Most take odd jobs to gather enough money to pay smugglers for the risky journey to Italy.

IOM and Libyan officials say the new upsurge of illegal migration from North Africa might have been prompted by fears of migrants and people smugglers that Libya and Italy would step up crackdown on illegal migration next month. Tripoli and Rome have reached an agreement on joint sea patrols to try to stem the flow of illegal migrants. The accord becomes effective on May 15.