MILAN — Spain will send a naval ship to Italian waters to pick up the 83 migrants who have been stranded in deteriorating conditions on a humanitarian group’s boat, the Spanish government said on Tuesday.
The office of the caretaker prime minister, Pedro Sánchez, a center-left Socialist, said a warship, Audaz, would depart from the southern Spanish port of Rota.
The vessel is expected to arrive at the Italian island of Lampedusa on Friday, the statement said, before then sailing to the main port on the island of Mallorca.
The announcement came as at least 15 migrants jumped into the sea from the rescue ship Open Arms, which is named for the organization that runs it, in desperate bids to reach the shores of the Italian island in the central Mediterranean after 19 days on the boat.
Italy’s hard-line antimigrant interior minister, Matteo Salvini, whose government collapsed on Tuesday, has refused port access to the ship, even though six other European countries have agreed to take in the migrants after they were rescued at sea off the coast of Libya.
Italy’s standoff with Open Arms had further raised tensions in the country’s governing coalition, as cabinet members from the Five Star movement, including the defense and transport ministers, were increasingly skeptical about the handling of the rescue ship by Mr. Salvini, leader of the right-wing League party.
Dozens of migrants have been evacuated in recent days because they were underage or ill, but 83 people remain on board the ship in conditions that Open Arms called “out of control” and “desperate.”
One migrant jumped off the ship early on Tuesday and was rescued by the Italian Coast Guard, followed by two groups, one of nine and another of five, who launched themselves into the sea wearing orange life vests.
All were seeking the shores of Lampedusa, a short distance away from the anchored ship.
A reporter with the Spanish public broadcaster TVE said the first jumper had refused to return to the Open Arms and was brought to Lampedusa instead, prompting others to follow his lead. The reporter said those jumping were “desperate and going mad” after 19 days trapped on board.
Video from the scene showed people wearing life vests floating in the sea, some in groups and some individually, with a Coast Guard vessel nearby and rubber dinghies trying to reach them.
Open Arms said the Italian Coast Guard had rescued all 15 jumpers and brought them to Lampedusa.
A spokeswoman for the charity, Laura Lanuza, said she heard from Open Arms crew members that “those who remain aboard are threatening to jump as well.” The Open Arms captain previously informed Italian authorities that the crew of 17 could no longer control the situation on board.
The question of how to handle migrant ships has been complicated by Italy’s refusal to allow migrant ships to dock, a policy that was imposed immediately after the populist coalition of the League and the Five Star Movement took office last June.
Shortly afterward, a ship made the long trip to Spain with 630 migrants after the government in Madrid opened its ports, but leaders there then sought to change their approach, arguing that international marine laws and European Union regulations required that rescued people be taken to the closest and safest port.
Spain also said at the time that European Union members needed need to find a long-lasting solution for dealing with migration that didn’t place an unfair burden on countries along the Mediterranean, the main route for migrants.
Open Arms sailed within a few hundred meters of Lampedusa last week after a court overturned Mr. Salvini’s ban on private rescue boats entering Italian waters. Mr. Salvini has appealed that ruling and warned that his ban on docking still holds.
Meanwhile, the Norwegian-flagged Ocean Viking, which is operated by two French humanitarian groups and has 356 rescued migrants aboard, has been sailing between Malta and the Italian island of Linosa as it waits for a port of safety to be assigned.
The Italian transport minister, Danilo Toninelli, said other European countries were turning their backs on Italy “and there is one person responsible: Matteo Salvini, who has weakened the government and as a consequence our position in Europe.”