When Italy heard that the mini-summit on Sunday would focus on reducing secondary migration - migrants moving within the European Union - and not primary migation - migrants getting into the European Union - its anti-immigrant prime minister Guiseppe Conte said he wouldn't attend.
The Lifeline is carrying 226 migrants rescued off the coast of Libya, Mission Lifeline said. Italy's transport minister, Danilo Toninelli, however, said it was unsafe for the 32-meter vessel to make the journey with so many people on board.
Earlier this month Salvini pledged to no longer let charity ships bring rescued migrants in Italy, leaving the Gibraltar-flagged Aquarius stranded at sea for days with more than 600 migrants until Spain offered them safe haven.
The crew of the ship had spotted the migrants early Thursday morning.
Mission Lifeline said it has still not been assigned a port, despite its requests.
Salvini has likened such rescue ships to taxi services that finish the job for migrant smugglers.
Matteo Salvini said the ship operated by the German aid group Mission Lifeline had loaded the migrants in Libyan waters after the Italian coast guard told it to leave the rescues to the Libyan coast guard.
Mr Salvini said the rescue was in Libyan waters, which Lifeline denies.
Since Mediterranean arrivals spiked in 2015, when more than a million refugees and migrants reached the bloc, European Union leaders have been at odds over how to handle them, the feud weakening their unity and undermining Europe's free travel area.
"The rescue, which happened in the Libyan rescue zone, was being coordinated by the Italian authorities and later on by the Libyan authorities".
Italy is storming ahead with its new tough stance against migrants, insisting it will not take "one more" refugee and warning the migration crisis could put the EU's survival at stake.
"We can't accept any one person".
The sum will be a "real budget with annual revenues and spending", said French President Emmanuel Macron after talks with the German leader, adding that Paris and Berlin hoped to have it in place by 2021.
"The next step is we try to talk to other European countries to get help because the people onboard need to [be evacuated] immediately", the NGO's co-founder told Euronews, which reported the vessel is still in worldwide waters.
But the government was placated after Merkel told them the text had been shelved.
Italy has seen more than 700,000 migrants arrive on its shores since 2013.
Data from the German interior ministry does indicate that the proportion of crimes committed by foreigners has gone up in the past five years, but this can not be attributed specifically to migrant arrivals.
An SWG poll this week showed two-thirds of Italians agree humanitarian boats should not be allowed in the country's ports.
Both vowed steps to better protect the EU's external borders by boosting the Frontex agency, fighting human traffickers and creating a fairer system of burden-sharing within the bloc.