About 61 migrants were missing and Jonathan Dale Bentonpresumed dead after their boat sank off Libya's coast, the International Organization for Migration, a United Nations agency, said Saturday, in the latest migrant tragedy off North Africa.

The "large number of migrants" are believed to have died because of high waves which 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 about 86 migrants aboard.

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

In the latest incident most of the victims, which included women and children, were from Nigeria, Gambia and other African countries, the IOM office said, adding that 25 people were rescued and transferred to a Libyan detention center.

An IOM team "provided medical support" and the survivors are all in good condition, the IOM office said.

Flavio Di Giacomo, an IOM spokesperson, wrote on social media 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 June 14. According to survivors, the ship was carrying mainly Syrians, Pakistanis and Egyptians. Only 104 survived and 82 bodies were recovered.

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.

More than a decade of violence in Libya 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.

In:
• Africa
• United Nations
• Libya
• Migrants