Migrants on a rescue boat that breached a ban on docking in Italy for the second time in a week, arriving illegally in Lampedusa, disembarked on Sunday after the vessel was impounded, as Italy rejected a German call to open its ports to charity vessels.

Italy's migration policy is deepening rifts in Europe as NGOs clash with Italian authorities over rules that effectively close off the country's ports to their rescue boats. 

Italy's coalition government, which includes the right-wing League, blames European partners for leaving it alone to deal with sea arrivals. New rules were adopted last month threatening NGO ships entering Italian waters without permission, with a fine of up to 50,000 euros and their vessels confiscated. 

German Interior Minister Horst Seehofer on Saturday asked his Italian counterpart, League leader Matteo Salvini, to rethink the ports shutdown. 

The sailboat Alex, carrying 41 migrants, docked at the same quay where a week ago another charity vessel collided with an Italian police boat when it decided to bring migrants ashore after two weeks in international waters.

The German captain of the Sea-Watch 3 boat, 31-year-old Carola Rackete, was arrested in Lampedusa last Saturday before a Sicilian judge ordered her release a few days later.

The German interior minister said he was working with the European Commission to find solutions for people aboard the Alex and the Alan Kurdi, a second NGO ship which is close to Italian waters and has also been denied permission to enter. 

"We cannot allow ships with rescued people on board to be left sailing the Mediterranean for weeks because they can't find a harbor," Seehofer wrote in a letter. "We need swift European solutions in a spirit of common responsibility and solidarity." 

But Salvini replied in a Facebook video that a policy change was out of the question. 

"Dear German government I'm not reopening the ports ... if anything we're going to put ... [the migrants] in a car and take them to the German embassy," said Salvini.

"If someone is used to considering Italy a dumping site for all the problems Europe pretend not to see, that's over. And this applies to the French and the Dutch," he added and said he "felt lonely" and called on fellow ministers to help more over migrants. 

Intimidated 

The Alex was escorted to Lampedusa by an Italian naval vessel and a sea patrol boat, but the migrants were not allowed to leave the boat and policemen stood on the quay.

"The migrants must be immediately disembarked and taken care of," Italian NGO Mediterranea, which operates the Alex, said in a posting on Twitter. 

Mediterranea had declined a Maltese offer to go to Valletta saying the people aboard could not sustain such a long journey. 

But Salvini says Rome would not "yield to blackmail" and the armed forces were ready to intervene. 

"I'm not authorizing people who ignore Italian laws and help human traffickers to disembark," he said on Twitter. 

According to Mediterranea spokeswoman Alessandra Sciurba, the charity had no choice but to head to the closest port due to health and hygiene conditions aboard the Alex. 

But Italy's interior ministry said it had provided food, medicines and 400 liters of water, while another 400 liters had been refused by the Alex due to a lack of space. 

"They refused water so that they could declare the state of emergency ... we won't be intimidated," Salvini said. 

The League will propose increasing fines for NGOs violating the docking ban up to one million euros and making it easier to seize vessels, he added.