Italy's new interior minister, Matteo Salvini, said on Sunday that from now on, "Italy, too, begins to say NO to the trafficking of human beings". Meanwhile Transport Minister Danilo Toninelli, a member of M5S and the minister in charge of the Italian coast guard, said that "this time everyone has to understand that global law can not mean that Italy should be abandoned".
"Our sole objective is to bring the people we've rescued, in hard conditions yesterday, to a port of safety", the group said in a statement. "Italy is done bowing its head and obeying".
Late on Monday, the Aquarius's rescue coordinator, Nicola Stalla, had said that it would be impossible for the entire group of migrants to make the journey to Valencia on board the rescue ship, as it would mean sleeping out in the open in deteriorating weather conditions.
The IOM and other humanitarian organizations argue it is not fair that a country such as Italy, which tends to be the first port of call, be responsible for the thousands of migrants that land on its shores.
A total 629 migrants - including pregnant women and scores of children - are now crammed on to the Aquarius ship after being rescued off the Libyan coast on Saturday and Sunday.
The Spanish prime minister Pedro Sanchez said he would give the ship "safe harbour" and that he wanted to help avoid a humanitarian emergency.
"The island can not continue looking the other way when it comes to respecting worldwide conventions", said the statement, which was signed by Salvini and Transport Minister Danilo Toninelli, who is nominally in charge of the ports.
Both Mr Muscat and new Italian premier Giuseppe Conte readily thanked Spain for the offer, with Mr Conte saying "it goes in the direction of solidarity". But front-line countries such as Italy and Malta say the burden needs to be shared out across the bloc.
Refugees International reminds European Union governments that while a fair mechanism for sharing the responsibility for Europe's recent refugee arrivals is urgently needed, the reality is that only a small fraction of the world's migrants and refugees ever reaches Europe.
By law, it would have been hard for Italy to refuse the boat a safe haven, as its own Coast Guard co-ordinated the rescues, picking up more than 280 migrants in its own vessels before transferring them to the Aquarius to be taken to safety.
SOS Mediterranean spokeswoman Mathilde Auvillain told The Associated Press the ship was "heading north following instructions received after the rescues and transfers" Saturday night.
"The island can't continue to turn the other way", the ministers said.