Rome/Valletta - An Italian tanker was heading Wednesday to rescue two stranded vessels carrying would-be immigrants near both an Italian island and Malta, amid a row between the two countries over who should take in the group, believed to number 140 people.

The Italian ship was destined for Tunisia when it changed its route to reach the area from where the would-be migrants sent a distress call, the ANSA news agency said citing Italian naval officials.

The stranded vessels were believed to be some 50 nautical miles south of the Italian islet of Lampedusa - waters in which Italy says rescue operations are the responsibility of Malta.

But Maltese authorities insist that because Lampedusa, the territory nearest to the stranded vessels is Italian, Rome should take in the would-be migrants.

"Malta is playing its part, and expects other countries to also do their duty in terms of international law, without excuses and mindful of humanitarian consideration," Darrell Pace, a spokesman for the Maltese Home Affairs Ministry told the German Press Agency dpa.

The spat between the two Mediterranean nations follows a similar row last month, when both refused to accept 166 migrants rescued by a Turkish freighter, until Italy eventually relented.

Italy and Malta are both European Union members, and illegal immigration is a burning issue for both countries in European Parliament elections scheduled in June.

In an uncharacteristic tone, Maltese Prime Minister Lawrence Gonzi launched a scathing attack on Italy on Tuesday, saying he was "disgusted" to hear that other countries in the Mediterranean were refusing to rescue people in distress.

But on Wednesday Italy's Foreign Undersecretary Stefania Craxi dismissed the Maltese allegations.

"I would like to point out that the Italian Coast Guard is the only one which has rescued people who have been shipwrecked in non- Italian territorial waters," she said.

"This has been done with great humanity and spirit of service - a great amount of work that is not being done by the governments of other Mediterranean states," she added. (dpa)