PRAGUE – The Czech prime minister announced unexpectedly on Tuesday his government will resign over unexplained business dealings of his rival Andrej Babis, the country’s finance minister.

Premier Bohuslav Sobotka said that he will meet President Milos Zeman this week to formally submit the government’s resignation.

Tuesday’s move reflects tensions in the ruling coalition about six months ahead of the parliamentary election.

Sobotka said there are suspicions that Finance Minister Andrej Babis, the country’s second richest businessman, avoided paying taxes in the past. Doubts have also surfaced about how he became wealthy.

Babis heads a centrist movement that is a favorite to win October’s ballot, paving the way for him to become prime minister. He previously denied any wrongdoing.

Sobotka’s Social Democrats are a distant second. The Christian Democrats are the third member of the coalition that was created in 2014.

Sobotka said it would be an option to fire Babis but that would mean his rival would be given extra time to campaign ahead of the vote.

“That’s the reason I’m opting for the only reasonable solution which is available, and that’s the government’s resignation,” Sobotka said during a hastily organized news conference.

“A trust of the public in politics is at stake,” Sobotka said.

The premier said the move will give the coalition a chance to form a government again, but without Babis. Another option is for Parliament to call early elections.

Babis and the presidential office didn’t immediately comment.

The president plays a key role in a crisis like this one because he has a right to select a new prime minister.

Babis’ centrist movement came in a surprise second in the 2013 parliamentary elections with an-anti corruption message

Babis, a billionaire sometimes dubbed the “Czech Berlusconi,” a comparison to Silvio Berlusconi – the Italian media tycoon who until recent years dominated his nation’s politics.