A rubber dinghy packed with 91 migrants that set out from Libyan shores in hopes of reaching Europe has apparently gone missing in the Mediterranean, the UN refugee agency said Thursday.
The inflatable boat carrying mostly African migrants departed from al-Qarbouli, 50 kilometre east of the capital Tripoli on February 8, said Osman Haroun, whose cousin was on board.
He hasn't heard from the 27-year-old Mohamed Idris, or his 10 other friends also on the boat, since.
News of the missing boat comes amid criticism of the European Union's lack of rescue missions in the Mediterranean Sea.
Member countries agreed earlier this week to end an anti-migrant smuggler operation involving only surveillance aircraft and instead deploy military ships to concentrate on upholding a UN arms embargo that's considered key to winding down Libya's relentless war.
Frontex, the EU border agency, said it deployed a plane to search for the missing boat.
Alarm Phone, a crisis hotline for migrants in need of rescue at sea, drew attention Thursday to what it called '' an invisible shipwreck,'' urging Libyan, Maltese and Italian authorities to share information about the day's rescue missions.
It said a black rubber boat with 91 people on board, reportedly hailing from Sudan, Niger, Iran and Mali, called the hotline in distress at 3:30 a.m. on February 9. The passengers managed to share their GPS coordinates minutes later, which put them in international waters north of Libya.
Alarm Phone passed the SOS to Italian and Maltese authorities and to the Libyan coast guard, an EU-trained force criticized by human rights groups, which patrols Mediterranean waters and intercepts migrants to keep them from reaching European shores.
The Libyan coast guard took five hours to respond to Alarm Phone's urgent request, and said it dispatched two ships to search for the missing vessel, without providing evidence.
Alarm Phone lost contact with the boat over two hours later, when it heard people panicking, saying the engine had failed. Migrants were slipping into the sea, they told the hotline, as water flooded the shrinking dinghy.
The International Organization for Migration cross-checked search and rescue records from Italy, Malta, Libya and the non-governmental Aita Mari rescue ship, but could not match the missing migrant boat with any recent interceptions or rescues.
Authorities have also yet to respond to requests put forward by Alarm Phone on Monday.
Both Alarm Phone and IOM say they fear the worst.
'' Tragically, the last hypothesis is that this could be another invisible shipwreck,'' said Marta Sanchez, a project officer with IOM's Missing Migrants project who examined the records.
Sanchez said IOM would wait a few days before officially recording the 91 people as missing, to see if any remains turn up.
The IOM tally of ''ghost boats'' lost in the Mediterranean Sea has been rising. Last year, the agency documented seven disappeared vessels carrying 417 people, a four-fold increase from the year before.
As of last October, roughly 19,000 migrants have drowned or disappeared on the sea route from Libya to Europe since 2014, according to IOM.