The 5-Star Motion is Parliament's largest get together because of assist from southern Italy, the place voters within the March election preferred Di Maio's promise of a minimal revenue for the unemployed.
Italy's president swore in western Europe's first populist government Friday, featuring a mix of anti-establishment and right-wing ministers who have promised an "Italy first" agenda that has alarmed Europe's political establishment.
Mattarella had objected to the coalition nominating anti-euro politician Paolo Savona as Minister of Economy and Finances and used his veto as President to block Conte from forming government.
While many officials in Brussels sought to ease tensions with Rome this week, and came to the defense of Mattarella after the president took a political risk by defending Italy's role in the European Union, a top official on Thursday issued a tough critique of Italy.
"The party is over" for migrants in Italy, he said, before visiting a so-called "hotspot", or reception centre, in the port of Pozzallo, where boat-borne arrivals are registered, photo-identified and fingerprinted.
Law professor Giuseppe Conte, Italy's new prime minister designate, speaks to the media to present his ministers list after being appointed by Italian President Sergio Mattarella on Thursday in Rome, Italy. The money would be better spent "building a future for them" in their home countries, Salvini said.
Prime Minister May congratulated Prime Minister Conte on his new role and on forming a new government.
A controversial agreement between Italy's former centre-left government and authorities and militias in Libya has triggered a decline in overall arrivals of some 75 percent since the summer of 2017.
The government's critics say its plan to repatriate migrants is unworkable and risks fomenting racism and politicising a humanitarian issue.
Salvini has long wanted his new post, from where he will aim to stop "the business" of migration, cracking down on people smuggling networks and speed up expulsions of illegal immigrants.
Matteo Salvini of the League, right, stands by Luigi Di Maio, leader of Five Star, on June 1.
French far-right leader Marine Le Pen tweeted: "It's a victory of democracy over intimidation and threats from the European Union".
"Gotta stay strong or the bully boys will be after you", he warned.
Announcing the ministers in his government, Conte said: "We will work with determination to improve the quality of life of all Italians".
The alliance between the M5S and the League will have only a relatively narrow majority in the Italian senate, easing concerns among investors and officials in Brussels over the new government's decision-making.
"As minister I will work with European partners and African countries", he said.