The International Organization for Migration reported on Saturday that at least 61 migrants were missing and presumed dead after their boat sank off Libya's coast in the latest such tragedy off North Africa.

The migrants are believed to have died because of high waves that swamped their vessel after it left from Zuwara, on Libya's northwest coast, the IOM's Libya office said in a statement to AFP.

Citing survivors, it said there were approximately 86 migrants aboard — including women and children — from Nigeria, The Gambia, and other African countries.

Twenty-five people were rescued and transferred to a Libyan detention center, said the IOM. It said the survivors were all in good condition and had received medical support from IOM staff.

Libya and Tunisia are principal departure points for migrants risking dangerous sea voyages in hopes of reaching Europe via Italy.

More than 153,000 migrants arrived in Italy this year from Tunisia and Libya, according to the United Nations refugee agency.

Italy's far-right Prime Minister Giorgia Meloni won elections last year after vowing to stop illegal migration.

Meloni's hard-right government has so far taken numerous measures to restrict the activities of charity ships that save people attempting the perilous crossing from North Africa.

Her approach to tackling illegal migration won praise from British Prime Minister Rishi Sunak during a visit to Rome on Saturday.

The two leaders vowed to stop migrant boat landings on their countries' shores and to step up efforts to combat people smugglers.

The United Nations has described the central Mediterranean migration route as the world's deadliest, claiming hundreds of lives each year.

Flavio Di Giacomo, an IOM spokesperson, wrote on social media platform X on Saturday that more than 2,250 people died this year on the central Mediterranean migrant route, a "dramatic figure which demonstrates that unfortunately not enough is being done to save lives at sea."

The Adriana, a fishing boat loaded with 750 people en route from Libya to Italy, went down in international waters off southwest Greece on 14 June. 

According to survivors, the ship was carrying mainly Syrians, Pakistanis and Egyptians. Only 104 survived, and 82 bodies were recovered.

In Libya, more than a decade of violence since the overthrow and killing of dictator Moamer Kadhafi in a NATO-backed uprising helped turn the country into a fertile ground for human traffickers who have been accused of abuses ranging from extortion to slavery.