About 170 people are feared to have died in two separate Mediterranean shipwrecks, the UNHCR says.
The Italian navy reports a ship sank off the coast of Libya with 117 people on board, while Moroccan and Spanish authorities have tried to find a lost boat in the western Mediterranean.
The UN’s refugee agency could not independently verify the death tolls.
More than 2,200 people lost their lives trying to cross the Mediterranean in 2018.
“We cannot turn a blind eye to the high numbers of people dying on Europe’s doorstep,” UN refugee high commissioner Filippo Grandi said in a press release.
“No effort should be spared, or prevented, from saving lives in distress at sea.”
The first boat reportedly disappeared with 53 people on board in the Alborán Sea at the western end of the Mediterranean.