Malta has been appealing for help with migrants from the rest of Europe
As many as 71 African migrants drowned after their boat sank in the Mediterranean Sea, eight of their companions have told Maltese police.
The survivors were rescued by a fishing vessel from a semi-submerged dinghy about 70km (40 miles) off Malta, then handed over to a Maltese military boat.
The ship and a military aircraft searched the area for other survivors but none were found, the police said.
Malta - the smallest EU member state - is a leading destination for migrants.
More than 1,000 have managed to reach the island so far this year, mainly from North Africa. On Sunday, more than 100 were brought ashore in two separate operations off the Maltese coast.
The last major loss of life off Malta's coast came in May 2007, when a small boat adrift went missing with at least 53 migrants on board.
"Notwithstanding that they know about [previous] tragedies, these desperate people still try and make the journey to Europe," Neil Falzon, a representative of the UN High Commissioner for Refugees in Malta, told the AFP news agency.
Mr Falzon said that if the number of fatalities was confirmed, it would serve to highlight "the need for assistance to these people".
In June, the European Parliament passed a controversial set of EU rules for dealing with illegal migrants, which allow those caught to be detained for up to 18 months and face a five-year re-entry ban.
Lawmakers backed the measures by a large majority despite opposition from many Socialist and Green parties, and condemnation from human rights groups.