Sea-Watch 3 skipper Carola Rackete faced jail time Saturday after forcing her way into Italy's Lampedusa port with a shipload of rescued migrants to end a lengthy standoff with authorities.
Sea-Watch spokesman Ruben Neugebauer told AFP the 31-year-old German captain was seized after manoeuvering the ship into port without authorisation on Friday night.
Rackete, described as a "pain in the neck" by Italy's far-right Interior Minister Matteo Salvini, was detained for forcing her way into port past a police vessel trying to block her, a crime punishable by between three and 10 years in jail.
She was escorted from the vessel and taken away in a car as Salvini slammed what he termed a "criminal act, an act of war," demanding that she be imprisoned.
An image grab taken from a video released by Local Team on June 29, 2019, shows migrants disembarking from the Sea-Watch 3 charity ship at the Italian port of Lampedusa
"Humanitarian reasons cannot justify unacceptable acts of violence towards those wearing uniform at sea," Italian media quoted regional prosecutor Luigi Patronaggio as saying.
Rackete will appear before a state prosecutor within 48 hours, her lawyer Leonardo Marino told reporters.
The 40 migrants on board were allowed to disembark and were taken to a reception centre on the island, some smiling, others in tears as they prepare to travel on to either France, whose interior ministry said it would take in ten of them, or to Germany, Finland, Luxembourg and Portugal.
The Italian coastguard then took control of the boat, anchoring it just off the coast.
"We put ourselves in the way to prevent (the ship) from entering the port. If we had stayed there, (the vessel) would have destroyed our speedboat," a police officer said in video footage posted on social media.
Residents and activists had gathered on the pier to watch the Sea-Watch 3 dock.
While a group of supporters applauded Rackete, others hailed her arrest, shouting "handcuff her", "shame" and "get lost!".
Former minister for ports, leftist lawmaker Graziano Delrio, said he was pleased "the people's suffering is over," comparing Rackete's actions to those of an ambulance driver who drives through a red light to attend an injured person.
Heinrich Bedford-Strohm, head of Germany's Protestant church group which is a key donor to Sea-Watch, slammed the arrest as "Europe's shame" while German Greens leader Robert Habeck said the real "scandal" was migrant drownings and Rackete's lack of an alternative.
Luxembourg Foreign Minister Jean Asselborn urged she be freed as "saving human lives is a duty and should never be a crime."
The dreadlocked skipper has become a leftwing hero in Italy for challenging Salvini's "closed-ports" policy and her NGO's head, Johannes Bayer, said Sea-Watch was "proud of our captain".
"She did exactly the right thing. She upheld the law of the sea and brought people to safety," he tweeted.
But Salvini, who heads the far-right League party, welcomed the arrest of the captain of the Dutch-flagged vessel.
"Mission accomplished," he tweeted. "Law-breaking captain arrested. Pirate ship seized, maximum fine for foreign NGO," said Salvini, whose hardline immigration stance has boosted his popularity.
Although many Lampedusa residents are sympathetic to the migrants, his party won a 45 percent vote share in last month's European elections on the island.
Italian Prime Minster Giuseppe Conte, in Japan for the G20 meeting, said: "I don't want to take the place of the judiciary... But the laws exist, whether we like it or not."
As Sicily prosecutors launched a probe into Rackete on suspicion of aiding illegal immigration she remained unrepentant while expressing concern about the psychological condition of those rescued off crisis-hit Libya.
"It's been almost 60h since we declared a state of emergency. No one listened. No one took responsibility. Once more it's up to us, to Cpt. #CarolaRackete and her crew, to (bring) the 40 people to safety," the charity said on Twitter.
With Italy restricting port entry, the Sea-Watch 3 was stuck in the Mediterranean during a heatwave since rescuing 53 migrants drifting in an inflatable raft off the coast of Libya 17 days ago.
Some had been allowed to disembark.
Nearly 500 migrants have landed on the Italian coast over the past 16 days, according to the interior ministry.
Meanwhile, the founder of Spanish migrant rescue charity Proactiva Open Arms said he was prepared to risk prison to save lives in the Mediterranean, following Rackete's example.
"If I have to pay the price through prison time or a fine in order to save the lives of some people, then I will do so," the group's founder Oscar Camps told AFP by telephone.
The Open Arms ship took to the waters off the Libyan coast on Thursday, a decision which could cost it a Spanish fine of up to 900,000 euros ($1 million), Camps said.