Madrid – A rescue ship with 87 migrants on board has arrived in southern Spain after days of sailing on the Mediterranean Sea.

The migrants, including twelve children from Sudan and Gambia, had been travelling on the ship for a week after being picked up off the coast of Libya. The ship, operated by the Spanish aid group Proactiva Open Arms, went to Spain after being barred from docking in Italy and Malta.

Those countries argued that the migrants were picked up in Libya's search-and-rescue zone and should be returned there. Migrants face arbitrary detention and severe abuses in conflict-wracked Libya, according to the United Nations.

The ship arrived at the port of Algeciras early Thursday, the aid group wrote on Twitter.

Crackdown on charity vessels

France is set to take in "about 20" of those rescued "in a spirit of European solidarity," a source in the Elysee Palace said.

Officials from the French asylum authority would travel to Spain shortly to identify persons in need of international protection, the source said.

France has taken in refugees from other rescue ships blocked at sea in recent weeks, but has refused to accept the ships themselves, arguing that under maritime law they should be received at the nearest safe port.

Italy has been cracking down on charity-run rescue vessels since last year, and in June its new far-right Interior Minister Matteo Salvini started barring them from its ports.

More effort to save refugees

Some 18,392 migrants and refugees arrived in Italy so far this year, compared to almost 120,000 in all of 2017 and over 180,000 in 2016, according to the International Organisation for Migration (IOM).

The sharp drop in arrivals came as Rome helped build up the Libyan coast guard to intercept migrant boats, carry out rescue operations, and bring those on board back to Libyan soil.

But charities running rescue vessels have blamed increased restrictions on their operations for a sharp hike in the numbers of migrants drowning in June and July this year.

Some 721 migrants died on central Mediterranean routes in those two months, compared to 597 in the same period last year, according to the IOM, despite the fall in the numbers crossing.