(In this August 2nd story, corrects para 3 to show boat has not been moved from Lampedusa)

Migrants on a wooden boat are rescued by German NGO Jugend Rettet ship "Juventa" crew in the Mediterranean sea off Libya coast, June 18, 2017. REUTERS/Stefano Rellandini

PALERMO, Italy (Reuters) - Italian coastguards seized a migrant rescue boat operated by a German aid group in the Mediterranean suspected of aiding illegal immigration from Libya, a prosecutor said on Wednesday.

Video showed the Iuventa, which is run by Jugend Rettet, arriving at the island of Lampedusa surrounded by several coastguard vessels after it was stopped at sea before dawn.

Police inspected the ship as soon as it docked and checked the crew passports. They later took charge of the boat.

Jugend Rettet said on Twitter it had received no information about the investigation. It could not be reached for further comment.

It was the first time Italian police have seized a humanitarian boat. The move came amidst growing suspicion over the role non-governmental organizations are playing in picking up migrants off the Libya coast and bringing them to Italian ports.

Ambrogio Cartosio, chief prosecutor in the western Sicilian city of Trapani, told a news conference his investigation into Jugend Rettet was ongoing and no one had yet been charged.

“The evidence is serious,” Cartosio said. “We have evidence of encounters between traffickers, who escorted illegal immigrants to the Iuventa, and members of the boat’s crew.”

Italian media reported the boat had two Syrians aboard who were taken to a refugee center, but that could not be immediately confirmed.

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“TAXI SERVICE”

Cartosio said there was no indication that Jugend Rettet had received any money from the Libya-based traffickers.

“It would be fantasy to say there was a coordinated plan between the NGOs and the Libyan traffickers,” he said.

Cartosio told a parliamentary committee in May that he had suspicions about certain humanitarian groups because some rescue crew seemed to know in advance where to locate the flimsy boats crowded with migrants.

Looking to regulate eight non-governmental groups which regularly hunt for migrants in the southern Mediterranean, the Italian government asked them this week to sign a code of conduct, including a demand that they carry an armed policemen on board their boats.

Jugend Rettet, which describes itself as an organization of young Europeans, was one of five groups that refused to sign up, but Cartosio denied a suggestion that there was any link between this refusal and the boat’s seizure.

The 5-Star Movement, which polls say is now the country’s biggest party, have accused NGOs of offering a “taxi” service to migrants, while the rightist Northern League party has said all their ships should be impounded.

The humanitarian groups say they are only interested in saving lives, warning that thousands of people would die if they were not out at sea. Despite their efforts, 2,200 migrants have died so far this year trying to reach Europe from north Africa.

Looking to turn the screws on the traffickers, Italy’s parliament authorized on Wednesday a limited naval mission to help Libya’s coastguard curb migrant flows.

Jugend Rettet says on its website it started patrolling the Mediterranean in July 2016 and has rescued 6,526 people in its first year of action.

“We want to put pressure on state actors to enforce the fundamental right to life and security even in the Mediterranean,” the group says.