Italy's Interior Minister Matteo Salvini remained defiant Tuesday in refusing to allow about 170 migrants to disembark from an Italian coastguard boat after it docked in Sicily for technical reasons.
The Diciotti vessel, which rescued the migrants five days ago, arrived at the port of Catania overnight "for a technical stopover".
Salvini was forced to allow the boat to dock but refused to let migrants onto land until the European Union committed to taking care of some of them.
"Either Europe begins to seriously defend its borders and shares the relocation of immigrants, or we will start taking them back to the port that they left," Salvini tweeted on Tuesday.
"Italy has already done its duty, and when it's too much, it's too much," said Salvini, who is also deputy prime minister and leader of the far-right League.
He has threatened to return the migrants to Libya if other European countries did not participate in a solution.
The boat had been stuck off the coast of the Italian island of Lampedusa since Thursday while Italy's populist government, in power since June, battled with Malta over who should take them in.
The Maltese government says the migrants refused the help of a Maltese boat because they wanted to reach Lampedusa.
The spat between Italy and Malta is the second in just over a month. It follows a fight over 450 rescued people who were eventually allowed to disembark in Italy after five European countries agreed to take 50 each.
Last week Malta allowed 141 migrants aboard the French NGO rescue vessel Aquarius to dock after an agreement to distribute them to a number of European countries.