Far-right Interior Minister Matteo Salvini has pulled his support for Italy's governing coalition and called for snap elections, deepening the country's political crisis.
Long-rumbling tensions between the 14-month-old coalition's populist leaders have peaked in recent days, with the row centred on the financing of a multi-billion-euro high-speed train line.
As the crisis appeared to come to a head, Prime Minister Giuseppe Conte held separate talks with Salvini and the country's president Sergio Mattarella.
Mr Salvini, whose hardline League Party has already called for snap polls, has clashed with his fellow Deputy Prime Minister Luigi di Maio of the anti-establishment Five Star Movement (M5S) party over a range of policies.
He stepped up the pressure today, saying there was no longer a majority to support a government and calling for new elections.
"Let's go straight to parliament to say there is no longer a majority... and quickly go back to the voters," he said.
Both houses of parliament are currently on recess for the holidays and are not due back until September.
In an allusion to the souring relationship between the coalition partners, Mr Salvini also denounced "repeated insults against me and the League by supposed allies".
The opposition has also called on the government to resign, arguing it no longer has a workable majority in parliament after Mr Di Maio voted against the Lyon-Turin rail project.
Italian media reported that Matteo Salvini, in earlier talks with Giuseppe Conte, set conditions for staying in the coalition - including the resignation of the transport, defence and economy ministers, who have resisted his projects and policies.
A gentler reshuffle was seen as possible. However, Mr Salvini himself has refrained from publicly attacking Luigi Di Maio over his opposition to the rail project, which involves an 8.6-billion-euro tunnel through the Alps.
Will Italy bring down the EU?
Opinion polls indicate Salvini's League party would win the election and could govern in alliance with another, smaller far-right party, Fratelli d'Italia.
"The League and M5S have been diverging in their vision for too long, on matters that are fundamental for the country," the League said in today's statement.
"This government's only option is to let Italians have their say" by calling elections, it added.
President Sergio Mattarella has insisted there must be a government in place to finalise the budget, a first draft of which has to be submitted to EU authorities by the end of September.
To that end, the president could name a government of technocrats and push the elections back to February or March.
The government is struggling to rein in its public deficit and its mammoth debt mountain of more than €2.3tn.