A migrant rescue NGO said it has lost contact with a migrant boat that was just south of Malta, and has accused the Armed Forces of Malta of "hanging up the phone without giving any information."
Alarm Phone said there were 78 people in distress on the vessel. The vessel was 35 nautical miles south of Malta when contact was last made at around midnight on Sunday.
It said it had also lost contact with a second migrant boat, carrying 55 people. "We tried to reach the so-called Libyan coastguard without success. European authorities fail to provide any information. We hope the people are still alive and that they will be rescued soon," the group said.
A third boat was carrying 85 people.
Alarm Phone said Libya, which it described as "Europe's ally," had intercepted hundreds of migrants and "returned them to war. The group said it was unclear whether the boat that were carrying 55 and 85 people respectively were among them.
There are also confusing reports about a group of migrants who landed in Sicily on Sunday. While the Italian media reported that 400 people had landed in Agrigento, Alarm Phone said the group was actually made up of 50 people.
Over the weekend, there were also reports of shipwrecks off the Tunisian coast.
Sources said the coming weeks could see dozens of migrant vessels leaving Libya and heading towards Europe.
Malta, along with most other Mediterranean EU states, has closed its ports to migrant vessels.
Almost 300 migrant men are being kept on three Captain Morgan vessels that are anchored just outside Maltese territorial waters. The boats were chartered by the government as a temporary solution. The company is being paid €3,000 daily for each vessel.
Women and children who were among the rescued migrants have been brought to Malta.
File photo