Italian Prime Minister Mario Draghi's coalition government was rocked by fresh turmoil Tuesday after the largest party in parliament split, with the foreign minister starting a breakaway group.

Luigi Di Maio said his decision to leave the Five Star Movement (M5S) -- the party he once led -- was due to its "ambiguity" over Italy's support of Ukraine following Russia's invasion.

But it follows months of internal tensions in the party, which has lost most of the support that propelled it to power in 2018 and risks being almost wiped out in national elections due next year.

As many as 60 former Five Star lawmakers have already signed up to Di Maio's new group, "Together for the Future", media reports said.

"Today I and so many others... are leaving the Five Star Movement," the foreign minister announced at a press conference.

"We are leaving what tomorrow will no longer be the first political force in parliament."

Di Maio played a key role in the rise of the once anti-establishment Five Star Movement, but as Italy's chief diplomat has embraced Draghi's more pro-European, pro-Atlanticist views.

He has backed the premier's strong support for Ukraine following Russia's invasion, including sending weapons for Kyiv to defend itself.

In this he has clashed with the head of Five Star, former premier Giuseppe Conte, who has argued that Italy should focus on a diplomatic solution.

But a majority of lawmakers -- including from the Five Star Movement -- backed Draghi's approach in March and again in a Senate vote on Tuesday.

Despite Italy's traditional ties to Russia, Draghi's government has sent weapons and cash to help Ukraine, while strongly supporting EU sanctions against Russia.

Foreign Minister Luigi Di Maio says he decided to leave the Five Star Movement (M5S) due to its 'ambiguity' over Italy's support of Ukraine following Russia's invasion
Foreign Minister Luigi Di Maio says he decided to leave the Five Star Movement (M5S) due to its 'ambiguity' over Italy's support of Ukraine following Russia's invasion AFP / Filippo MONTEFORTE

Conte had warned against Italy getting involved in an arms race.

"We have contributed by sending three lots of weapons. Now it seems to us our contribution would be more precious on the diplomatic front," he said earlier this month.

But Di Maio had harsh words for his party and its leader, without citing Conte by name.

"In these months, the main political force in parliament had the duty to support the diplomacy of the government and avoid ambiguity. But this was not the case," he said.

"In this historic moment, support of European and Atlanticist values cannot be a mistake," he added.

The Five Star Movement, he said, had risked the stability of the government "just to try to regain a few percentage points without even succeeding".

Despite the friction, senators agreed by 219 votes to 20 a resolution Tuesday in support of Draghi's policy, just days before an EU summit later this week.

The compromise resolution grants more involvement by parliament in decisions, including over weapons shipments -- something sought by Conte.

Draghi, a former European Central Bank chief who visited Kyiv last week with the leaders of France and Germany, had earlier Tuesday made clear his course was set.

"Italy will continue to work with the European Union and with our G7 partners to support Ukraine, to seek peace, to overcome this crisis," he told the Senate, with Di Maio at his side.

"This is the mandate the government has received from parliament, from you. This is the guide for our action."

The Five Star Movement stormed to power in 2018 general elections after winning a third of the vote on an anti-establishment ticket, and stayed in office even after Draghi was parachuted in to lead Italy in February 2021.

But while it once threatened to upend the political order in Italy, defections, policy U-turns and dismal polling have left it struggling for relevance.

"Today ends the story of the Five Star Movement," tweeted former premier Matteo Renzi, who brought down the last Conte government by withdrawing his support.