The head of Italy’s anti-establishment Five Star Movement (M5S), which co-governs the country, was set to step down as party leader on Wednesday in a move likely to trigger political shockwaves.

M5S is the largest party in Prime Minister Giuseppe Conte’s coalition government, and Luigi Di Maio’s exit could further weaken an already fragile alliance with the center-left Democratic Party (PD).

Di Maio, 33, was expected to announce his resignation at a party meeting in the afternoon, Italian newspapers said.

That comes days ahead of a key regional poll putting the M5S and PD against Matteo Salvini’s right-wing opposition party, the League.

The League, which enjoys a significant lead in national polls, hopes that defeating the M5S and PD on Sunday in Emilia Romagna – a historic heartland of the left – will spark a crisis and bring down the government.

A League victory would increase tensions considerably, with the PD likely to blame the M5S for refusing to join forces behind a single candidate – thus splitting the anti-Salvini vote. The governing coalition’s main stabilizing factor is a joint fear of snap elections which could hand power to Salvini.

The M5S was likely to perform particularly badly, according to the last polls ahead of the ballot.

Di Maio was expected to remain foreign minister, but reportedly told relatives “this is the time to take a step back, I am exhausted”, online Italian newspaper TIP said.

Read more: thelocal.it