"Italy, too, begins to say NO to the trafficking of human beings, NO to the business of clandestine immigration," Italy's new Interior Minister said.
A ship carrying hundreds of migrants was stuck at sea Monday after Italy and the small Mediterranean island nation of Malta both refused to allow the rescue vessel to dock.
Aid group SOS Mediterranee said the 629 passengers aboard the Aquarius were caught up in a crackdown promoted by the right-wing partner in Italy's new populist government, which has vowed to stop the country from becoming the "refugee camp of Europe."
Those aboard the ship included 400 people picked up by the Italian navy, that country's coast guard and private cargo ships who were transferred onto the vessel. The crew of the Aquarius also pulled 229 migrants from the water or from traffickers' unseaworthy boats Saturday night, including 123 unaccompanied minors and seven pregnant women.
Malta said the rescue operations took place in international waters off Libya and were coordinated by Italy.
Italian Premier Giuseppe Conte said he personally contacted Malta's prime minister, Joseph Muscat, to "take on the human assistance of persons in difficulty aboard the Aquarius."
But Muscat, "while comprehending the situation," rebuffed him, Conte said in a Facebook post late Sunday.
Like Malta, Italy didn't appear to be budging.
Italy's firebrand interior minister, Matteo Salvini, who leads the anti-immigrant League party in the governing coalition, has long railed against what he depicts as Europe's failure to show solidarity with Italy during the migrant crisis in recent years.
"Starting today, Italy, too, begins to say NO to the trafficking of human beings, NO to the business of clandestine immigration," Salvini tweeted Sunday.
More than 600,000 migrants have reached Italy by boat from Africa in the past five years. Numbers have dropped dramatically in recent months, but rescues have increased in recent days.
After leading an hours-long meeting with his coalition leaders Sunday night at the premier's office, Conte said Italy was sending two motorboats with medical staff aboard in case the migrants needed help. He made no mention of whether or when the Aquarius might be permitted to get into port.
Salvini and Italian Transportation Minister Danilo Toninelli, who is part of the 5-Star Movement faction in the new government, said in a joint statement Sunday that it was Malta's responsibility to "open its ports for the hundreds of the rescued on the NGO ship Aquarius."
"The island can't continue to turn the other way," the ministers said. "The Mediterranean is the sea of all the countries that face it, and it (Malta) can't imagine that Italy will continue to face this giant phenomenon in solitude."
Earlier, Malta said in a statement that the Aquarius took on the passengers in waters controlled by Libya and where Italian authorities in Rome coordinate search-and-rescue operations.
The Maltese Rescue Coordination Center "is neither the competent nor the coordinating authority," the statement said.
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 Rome-based rescue coordination center gave the instructions.
The aid group said in a statement it had taken "good note" of Salvini's stance, as reported earlier by Italian media. It added that the Aquarius "is still waiting for definitive instructions regarding the port of safety."
SOS Mediterranee said Maltese search-and-rescue authorities were contacted by their Italian counterparts "to find the best solution for the well-being and safety" of the people on the ship.
Human rights groups oppose returning rescued migrants to Libya, where many are held in inhumane conditions, poorly fed and often forced to do slave labor.
Libya was plunged into chaos following a 2011 uprising. The lawlessness in Libya has made it a popular place for migrants to try to depart for Europe.
Driven by violent conflicts and extreme poverty, hundreds of thousands of migrants have reached southern Europe in recent years by crossing the Mediterranean with the help of smugglers.
The United Nations says at least 785 migrants have died crossing the sea so far this year.