Two aid groups operating a rescue ship in the Mediterranean have strongly condemned a decision by Italy to order its seizure, rejecting an accusation that the vessel was being used to illegally dump toxic waste at ports in southern Italy.
Italian magistrates on Tuesday ordered the Aquarius, which is chartered by Doctors Without Borders (MSF) and the SOS Mediterranee groups, to be impounded.
The vessel, which has saved thousands of migrants since 2016, is currently docked in the French port of Marseille.
According to Italian media, Aquarius was suspected of passing off 24 tonnes of potentially toxic waste as ordinary waste - an accusation denied by the groups.
"SOS Mediterranee categorically refuses any accusation of being involved in illegal activities," the group said in a statement.
"Standard procedures, that have not been questioned by authorities so far, have always been followed by the Aquarius," it added.
SOS Mediterranee called the action by the Italian authorities a "politically driven attack" and called on the French authorities to use restraint in the implementation of Italy's seizure order.
MSF meanwhile called the decision by the prosecutor's office a "disproportionate and unfounded measure".
"After two years of defamatory and unfounded allegations of collusion with human traffickers, judicial investigations, and bureaucratic obstacles against our humanitarian work, we are now accused of organised crime aimed at illicit waste trafficking," Karline Kleijer, MSF's head of emergencies, said in a statement.
"This latest attempt by the Italian authorities to stop humanitarian lifesaving search and rescue capacity at any cost is sinister."
The seizure was ordered after an investigation by the Italian prosecutor's office into how leftover food, clothes of rescued people and waste from the ship's medical activities were handled.
MSF and SOS Mediterranee say all rules were followed and the Italian authorities never raised an alarm over the issue.
"The in-port operations, including waste management, of MSF's search-and-rescue vessels have always followed standard procedures. Relevant authorities did not question these procedures nor did they identify any hazard for public health since MSF began search and rescue operations in 2015," MSF said.
In June, Italy's new Interior Minister Matteo Salvini blocked the Aquarius, carrying 629 refugees and migrants, from docking at its ports.
The move by the far-right leader, who is also a co-deputy prime minister, caused a public outcry with thousands in France taking part in rallies to express their anger at the efforts to stop the last migrant rescue ship operating off Libya's coast.