ROME — A Spanish aid group accused Italian authorities of putting humanitarian operations in the Mediterranean at risk on Monday, after its migrant rescue boat was impounded on suspicion it was aiding illegal immigration.

The Proactiva Open Arms group, which has saved more than 5,000 migrants since the start of 2017, had its boat impounded at the port of Pozzallo in Sicily, where it arrived on Saturday with more than 200 people rescued off the coast of Libya.

The group had refused to hand the migrants over to the Libyan coastguard, despite warnings from Rome and what the NGO claimed were death threats from the Libyans.

The prosecutor’s office of Catania in eastern Sicily has opened an investigation into Proactiva Open Arms and three of its leaders for criminal conspiracy to promote illegal immigration.

"Today it seems that solidarity has become a crime," said Open Arms co-founder Oscar Camps at a press conference in Barcelona.

"What is being done is the blocking of intervention of humanitarian organisations at sea. There are fewer and fewer NGOs doing this work and the objective is that there are none any left," he said.

"Finally an Italian prosecutor’s office is blocking human trafficking!" said Matteo Salvini, leader of the far-right League, which leads the rightwing coalition that won the largest percentage of the vote in Italy’s March 4 general election.

One in every 17 migrants dead

Last Thursday, the Open Arms ship went to the aid of two boats that were in difficulty 73 nautical miles (135 nautical kilometres) off the Libyan coast, after being alerted by the Italian coastguard.

But Italian authorities then informed the NGO’s ship that the Libyan coastguard was in charge.

A Libyan coastguard speedboat arrived at the scene after an hour, but the NGO refused to transfer the migrants despite the threats it claims to have received.

The ship was allowed to dock in Pozzallo on Saturday by the authorities because of the "frail condition of the migrants on board".

Following controversial agreements made by Rome with Libyan authorities and militias, migrant landings have dropped by more than 60 percent since the summer of 2017.

So far this year Italy has recorded 6,100 arrivals. In that time at least 358 migrants have died or are missing off the coast of Libya, according to the International Organization for Migration (IOM).

That means one migrant dead for every 17 that arrive in Italy, significantly up from the rate of one for every 33 over the same period last year. — AFP