ROME (AP) — The Italian news agency ANSA says a Spanish non-governmental organization's migrant rescue ship has been sequestered in Sicily by prosecutors' orders.

The seizure took place Sunday in Pozzallo port, where a day earlier the Proactiva Open Arms' vessel brought 216 migrants it had rescued last week in the Mediterranean north of Libya.

ANSA says Catania Prosecutor Carmelo Zuccaro is investigating three people for suspected criminal association for illegal immigration, including the commander of the boat.

Officials of the NGO couldn't immediately be reached for comment. ANSA quoted lawyer Rosa Emanuela Lo Faro, representing the commander, as saying "I guess they've instituted the crime of solidarity."

The NGO has said a Libyan coast guard vessel threatened to shoot its rescue dinghies if they didn't offload the migrants rescued in international waters.