Italian authorities have detained the migrant rescue ship Humanity 1 in the southern port of Crotone.
The ship, operated by the NGO SOS Humanity, docked on Monday carrying 77 migrants who had been rescued over the weekend.
The detention comes after a dispute between SOS Humanity and the Libyan Coast Guard over the rescue of up to 100 migrants in international waters.
SOS Humanity said that it was falsely accused of failing to coordinate with Libyan authorities and of endangering the lives of migrants during the rescue operation.
The organization said its intervention on Saturday was in response to a distress call it received from three migrant boats carrying approximately 100 individuals while sailing in international waters off Libya and Tunisia.
According to the organization, a Libyan patrol boat attempted to stop its efforts by force after threatening its staff and the migrants with an automatic rifle.
The intervention led to people jumping into the water, at least one person drowning, and families being separated, with some migrants being picked up by the NGO and others by the Libyans, the organization added.
Italy has frequently impounded charities' rescue ships under a migration decree issued by Prime Minister Giorgia Meloni's right-wing government last year.