Five Star's leader Luigi di Maio said talks today had been "productive" and that negotiations were still ongoing over who will become prime minister.
"One of the hypotheses is to pick a third person who has a high profile and is trusted by Italian citizens and Italy's global partners", Vincenzo Spadafora, a close aide to 5-Star leader Luigi Di Maio, told the Corriere della Sera.
Press agency AGI reported Di Maio made a brief call to the president's office to "announce that they are ready from tomorrow [Monday] to report on everything, including the name of the prime minister". President Mattarella has asked to meet Di Maio at 4.30 pm and Salvini at 6 pm, a statement said.More news: NHC eyeing tropical disturbance in the Gulf of Mexico
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If the head of state accepts the nomination, the position could be filled within days.
The progress is likely to clear the way for a coalition government formed of the two parties. These measures are likely to set Rome on a collision course with Brussels as the new government has vowed to ignore the budgetary restrictions now in place due to the Italian government's deficit.
Di Maio has softened Five Star's previously antagonistic tone on Europe, but his party and the League have vowed to take tough stances with Brussels on issues like EU fiscal rules amid widespread Italian discontent over the country's economic malaise and a lack of European solidarity on dealing with migration. Together they will be able to hold a majority in both houses.