ROME (Reuters) - Italian Foreign Minister Luigi Di Maio accused Khalifa Haftar’s administration in eastern Libya of “unacceptable” behaviour on Thursday for detaining 18 sailors who were seized while fishing in the southern Mediterranean. Libyan patrol boats detained two Sicilian fishing boats on Sept. 1 and brought the crews to Benghazi, where the military commander Haftar holds sway. The men were accused of operating in Libya’s territorial waters -- a fact disputed by Italy. Relatives of the sailors, who include Italians and Tunisians, have set up camp outside parliament to draw attention to the case amid reports that Haftar wants Italy to hand over four convicted human traffickers in return for freeing the fishermen. “Detaining people who violate a self-proclaimed zone is unacceptable ... just as it would be unacceptable if someone were to tell us that they will release the Italians if we release their nationals,” Di Maio told parliament. Khaled al-Mahjoub, a spokesman for Haftar’s Libyan National Army (LNA), said the fishermen had acted illegally. “Entering regional economic waters is a crime,” he told Reuters. Rosetta Incargiola told Reuters her son Pietro Marrone was captain of one of the boats, the Medinea, which had been seeking highly prized red prawns in the Mediterranean. “My son has called me just once, 16 days after his arrest. He told me he was fine, but he asked us to do everything to help them,” Incargiola said outside parliament. “The government must do something immediately. We are suffering a lot.” The fishing grounds have been disputed since 2005, when Libya’s then ruler, Muammar Gaddafi, unilaterally extended Libyan territorial waters to 74 nautical miles offshore from 12. Haftar, who controls eastern Libya, is trying to enforce this. Rome has never recognised the revised boundary and the owner of the Medinea, Marco Marrone, said his boat was 40 miles north of Benghazi when it was seized. Libya has been without strong central rule since Gaddafi was toppled in 2011 and rival camps have set up parallel administrations in the east and west since 2014. Italy has publicly backed the Tripoli-based Government of National Accord (GNA) and has had difficult relations with Haftar. It has sought to work with both administrations to try to slow the flow of illegal migrants to Italy. Italian media reported that Haftar wanted the release of four Libyans who were arrested in Sicily in 2015 and subsequently sentenced to up to 30 years in jail for allegedly organising a crossing that resulted in the deaths of dozens of migrants. The four men denied being people smugglers, saying they were soccer players looking to join European clubs. Al-Mahjoub declined to comment on any possible exchange deal, but said the families of the imprisoned quartet had asked the Libyan authorities to intervene on their behalf.