The UN’s refugee agency made an urgent appeal for 500 asylum seekers stuck on boats in the Mediterranean to be allowed to disembark, calling it a “race against time” as bad weather approaches. The 507 migrants and refugees are stranded on two NGO rescue vessels, which picked them up off the coast of Libya in recent days. “It is a race against time,” said Vincent Cochetel, the UNHCR’s special envoy for the central Mediterranean. “Storms are expected and conditions will only get worse. To leave people who have fled war and violence in Libya on the high seas in this weather will only inflict more suffering.” NGO rescue vessels should be applauded for their work, not “stigmatised and criminalised,” the UNHCR said, adding that many of the migrants have suffered “terrible abuses” in Libya. But the agency got short shrift from Italy, where ports have been closed to rescue vessels since last summer, in a policy forged by Matteo Salvini, interior minister and leader of the hard-Right League party. In a Facebook post, he said he was working to block the boats. "I will let you know how this ends. I will not give up," he wrote. A "rhib", an inflatable dinghy, belonging to the 'Ocean Viking' rescue ship, operated by French NGOs SOS Mediterranee and Medecins sans Frontieres (MSF), transports rescued migrants  Credit: Anne Chaon/AFP Around 350 of the migrants are on board the Ocean Viking, a Norwegian-flagged rescue ship operated by the humanitarian charities SOS Méditerranée and Medecins Sans Frontieres. The other 150 are on board the Open Arms, a Spanish rescue ship.  The UN called for them all to be allowed to disembark in a safe port. Mr Salvini and the populist government have repeatedly suggested that  Tunisian ports should be considered safe, questioning why migrants should be brought to Italy, Malta or other European countries. So far this year, around 600 migrants have died trying to reach Europe from North Africa by sea. Mr Salvini has drastically reduced the number of migrants reaching Italy by sea – just 4,265 have arrived so far this year, down nearly 80 per cent on the same period last year. His mantra that “the good times are over” for illegal migration has gone down well with millions of Italians, with the League polling around 38 per cent as Italy looks set to face new elections after Mr Salvini pulled the plug on the 14-month coalition with the Five Star Movement.