At least 170 people are feared dead after they went missing from two separate shipwrecks on the Mediterranean Sea that left from Libya and Morocco, the United Nations said.
"Some 53 people have died on the Alborán Sea, western Mediterranean, according to recent information from NGO sources," the UN High Commissioner for Refugees (UNHCR) said in a statement on Saturday.
"One survivor is understood to have been rescued by a passing fishing boat after being stranded for more than 24 hours at sea and is receiving medical treatment in Morocco."
UNHCR added that rescue vessels from Moroccan and Spanish rescue searched for the boat and survivors "for several days to no avail."
Meanwhile, the non-governmental organization Sea Watch said in a statement Saturday night that there were only three survivors from a shipwreck in the central Mediterranean.
"They say they left Libya on an inflatable dinghy with 120 people. There are 117 people dying or missing," head of the Sea Watch Mission, Kim Heaton-Heather said.
"The three castaways reported to the International Organization for Migration that they had been at sea without assistance for more than three hours before the intervention of the Italian Navy plane."
The UNHCR said it was "deeply saddened" over the reports and added that it has not been able to independently verify the death toll.
"The tragedy of the Mediterranean cannot be allowed to continue," said UNHCR's Filippo Grandi.
"We cannot turn a blind eye to the high numbers of people dying on Europe's doorstep. No effort should be spared, or prevented, from saving lives in distress at sea."
Meanwhile, Sea Watch reported that it had rescued 47 people from "a dinghy in distress" off the coast of Zuwarah, Libya on Saturday afternoon.
"They are safe on board Sea Watch 3 where they are receiving medical attention," the NGO said.
Italy's hardline Interior Minister Matteo Salvini closed the country's ports to migrant boats in June and the populist government has passed new anti-immigrant laws.
On Sunday, Salvini posted on Facebook: "I have not been, am not and I will never be an accomplice of human traffickers."
He added that mayors and governors "instead of denouncing the alleged violation of the |rights of illegal immigrants ... should take care of the work and welfare of their citizens, given that they are the Italians to pay their salary."
The International Organization for Migration puts the number of migrants and refugees arriving in Europe last year at close to 142,000, most of whom made the perilous crossing of the Mediterranean Sea.
The UN agency reported more than 2,200 migrants as missing or dead in the Mediterranean in 2018.
"UNHCR is concerned that actions by States are increasingly deterring NGOs from conducting search and rescue operations, and is calling for these to be lifted immediately," the refugee agency said in a statement Saturday.