Two shipwrecks in recent days have brought to more than 1,300 the number of migrants who have died this year trying to cross the Mediterranean, the UN said on Tuesday.
In the most recent disaster, 163 people are feared dead or missing after a boat sank off the Libyan coast on Sunday, the UN refugee agency said.
UNHCR cited one of its partners, the International Medical Corps charity, as saying that a woman and six men were rescued by Libyan coastguard after the shipwreck.
A further 82 people are feared dead or missing after a rubber dinghy sank late on Friday in open sea off the Libyan coast with 132 people on board, UNHCR said.
Some 50 people were rescued from the dinghy and reached the Sicilian port of Pozzallo on Sunday, UNHCR stated.
Over 43,000 migrants and asylum seekers have used the dangerous Central Mediterranean route from North Africa to reach Italy so far this year, UNHCR said.
UNHCR stressed the "crucial importance" of operations to save lives in the Mediterranean involving the Italian coastguard, the European Union border and coastguard agency Frontex and charity rescue vessels.
"There is also an urgent need to address the root causes which lead people to move as well as to offer credible alternatives to these dangerous crossings for people in need of international protection, including accessible and safe ways to reach Europe such as family reunification, relocation and resettlement," UNHCR stated.