Dozens of migrants rescued in international waters off Tunisia are still stranded 15 days later as authorities refuse to allow the boat carrying them to access a nearby port, the UN said Friday. Egyptian tugboat Maridive 601 rescued 75 migrants off the southern Tunisian coast in late May after they embarked from Libya, a key launchpad for sub-Saharan Africans making dangerous bids to reach Europe by sea. The vessel has been anchored since May 31 off the southern port of Zarzis, where authorities have refused to allow the vessel to dock despite an appeal by the boat's captain. The UN's International Organisation for Migration said on Friday that the vessel's owners have since been providing those aboard with food and water. Tunisian officials contacted by AFP refused to comment on the situation, although an interior ministry official said last week, on condition of anonymity, that "the migrants want to be welcomed by a European country". Humanitarian groups say Tunisia, which has already received several hundred migrants since the start of the year, is reluctant to take on more new arrivals, demanding that they agree to be repatriated before being allowed to enter Tunisian territory. The IOM said at least 32 unaccompanied minors were on the boat, and offered to help Tunisia host the migrants. It added that 10 of those aboard the boat - nine Egyptians and a Moroccan - had expressed interested in returning home. "We ask for the reinstatement of mechanisms to care for migrants rescued at sea" to prevent similar incidents in the future, said IOM's Tunisia head Lorena Lando. In 2018, Tunisian authorities prevented more than 11,400 irregular crossings of the Mediterranean, Interior Minister Hichem Fourati told parliament on Friday. He said they had also arrested hundreds of people suspected of involvement in people-trafficking. So far this year, Tunisian forces have intercepted some 428 clandestine migrants, he added.