Rome, May 20 (IANS): Italy has instructed the aid ship Sea-Eye 4, with over 400 migrants on board, to dock in the Sicilian town of Pozzallo, even though the vessel was headed for Palermo at the other end of the Mediterranean island.

The German operating organisation Sea-Eye on Thursday criticized the decision.

"It is totally incomprehensible to us that Pozzallo should be the nearest safe haven for people when we are in Palermo," Sea-Eye spokesperson Gorden Isler told dpa news agency.

He said the measure could be classified as "harassment".

According to Italian news agency ANSA, the authorities officially assigned the port south-east of Ragusa on Wednesday evening, after the ship, carrying a total of 415 boat migrants, was already en route to Palermo, whose Mayor had offered to help.

"The rescued migrants, including about 150 children as well as pregnant women, will have to spend two additional nights on the ship due to the journey," Isler said, speculating that Rome was intent on delaying the organization's mission in the future.

The Sea-Eye 4 had rescued the migrants during several operations over the past days.

Refugees and migrants repeatedly attempt the dangerous crossing to Europe from Libya, often trying to reach Italy as the first point of entry.

According to the UN's International Organization for Migration, more than 575 people have died in the Mediterranean this year.