VALLETTA, Malta (AP) — A Maltese special operations team on Thursday boarded a tanker that had been hijacked by migrants rescued at sea, and returned control to the captain before escorting it to a Maltese port.

Armed military personnel stood guard on the ship's deck, and a dozen or so migrants were also visible, as the Turkish oil tanker El Hiblu 1 docked at Boiler Wharf in the city of Senglea. Several police vans were lined up on shore to take custody of the migrants for investigation, and four migrants were led off the ship in handcuffs.

Authorities in Italy and Malta on Wednesday said that the group had hijacked the vessel after it rescued them in the Mediterranean Sea, and forced the crew to put the Libya-bound vessel on a course north toward Europe.

Italy's interior minister, Matteo Salvini, said the ship had rescued about 120 people and described what happened as "the first act of piracy on the high seas with migrants" as the alleged hijackers. Malta has put the number of migrants rescued at 108.

Maltese Prime Minister Joseph Muscat said on Twitter that the nation's armed forces had conducted a "sensitive operation on high seas."

"We do not shirk responsibility despite our size," he said, pledging to follow international rules.

The ship had been heading toward Italy's southernmost island of Lampedusa and the island nation of Malta when Maltese forces intercepted it.

Maltese armed forces established communications with the captain while the ship was still 30 nautical miles off shore. The captain said he was not in control of the vessel "and that he and his crew were being forced and threatened by a number of migrants to proceed to Malta," the armed forces said. No details were given of what force and threats were used.

The special team that restored control to the captain was backed by a patrol vessel, two fast interceptor craft and a helicopter.

There was no immediate word on the condition of El Hiblu 1's crew.

Humanitarian organizations say that migrants are mistreated and even tortured in Libya, and have protested protocols to return migrants rescued offshore to the lawless northern African nation. Meanwhile, both Italy and Malta have refused to open their ports to humanitarian ships that rescue migrants at sea, which has created numerous standoffs as European governments haggle over which will take them in.

While Italy's interior minister called the hijacking an act of piracy, the humanitarian group Sea Watch disputed that term, saying the actions "were in self-defense against the deadly consequences forced upon them by Europe's inhumane border policy."

A private group that operates a rescue ship and monitors how governments treat migrants, Mediterranea, urged compassion for the group on the hijacked vessel and said it hoped European countries would act "in the name of fundamental rights, remembering that we are dealing with human beings fleeing hell."

Mass migration to Europe has dropped sharply since 2015, when the continent received 1 million refugees and migrants from countries in the Middle East, Asia and Africa. The surge created a humanitarian crisis in which desperate travelers frequently drowned and leading arrival spots such as Italy and Greece struggled to house large numbers of asylum-seekers.

Along with the dangerous sea journey itself, those who attempt to cross the Mediterranean risk being stopped by Libya's coast guard and held in Libyan detention centers that human rights groups have described as bleak places where migrants allegedly suffer routine abuse.

EU members "alert the Libyan coast guard when refugees and migrants are spotted at sea so they can be taken back to Libya, despite knowing that people there are arbitrarily detained and exposed to widespread torture, rape, killings and exploitation," said Matteo de Bellis, an international migration researcher for Amnesty International.

European Union member countries, responding to domestic opposition to welcoming immigrants, have decided to significantly downscale an EU operation in the Mediterranean, and have decided in principle to withdraw their ships, which would mean continuing the mission with air surveillance only. A formal decision has to be made by Sunday, when the mission mandate expires.

"This shameful decision has nothing to do with the needs of people who risk their lives at sea, but everything to do with the inability of European governments to agree on a way to share responsibility for them," de Bellis said.

Commercial ships have been increasingly caught between European governments hostile to taking in new migrants and the international maritime law's obligation to save people at sea.

Last November, dozens of migrants of a variety of nationalities seized control of a container ship that had picked them up in the Mediterranean, barricading themselves inside and refusing to disembark in the Libyan port of Misrata. After 10 days, Libyan authorities forcibly removed them from the ship and brought them to a detention center.

During the standoff, several migrants on the vessel told the AP that six commercial ships had seen their rickety boat foundering but passed them by before they were picked up by the seventh.

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Barry reported from Milan. Lori Hinnant in Paris, Lorne Cooke in Brussels and Vanessa Gera in Rome also contributed.