ZAGREB (Reuters) - The junior partner in Croatia’s ruling centre-right coalition on Friday quit the government over a row with the prime minister, raising the prospect of a possible snap election.

Prime Minister Andrej Plenkovic on Thursday fired three cabinet ministers from the Most (Bridge) party after they failed to follow him in rejecting opposition demands for the finance minister to resign.

Most said on Friday all four of its ministers would quit.

“By this we show that our primary goal is not keeping posts, but to prevent a constitutional crisis,” said Most party leader Bozo Petrov, who is also the speaker of parliament.

Plenkovic said on Thursday he would seek a new parliamentary majority but that he was ready for a snap poll if the talks on forming a new coalition failed.

The conservative HDZ party, which leads the cabinet, said it had collected enough signatures from parliamentary deputies for the removal of Petrov as parliament speaker.

Petrov said he would put the party’s request on the agenda after a parliamentary debate about the finance minister.

Analysts believe the growing tension between the coalition partners stems from competition for voters ahead of municipal elections to be held on May 21.

“A new stable cabinet is unlikely to be formed before municipal elections, and then a lot may depend on the results of those elections,” political analyst Zarko Puhovski said.

A previous coalition, comprising the HDZ and Most, collapsed last June after just six months. That led to a snap election in September.

The Most party has backed opposition calls for Finance Minister Zdravko Maric to step down because of a financial crisis at Croatia’s biggest private firm, Agrokor [AGROK.UL]. Maric was a senior executive at the ailing company until 2016.

Plenkovic said Maric was not responsible for Agrokor’s financial results.

Parliament is due to discuss the opposition demand against Maric next Wednesday.

The government adopted measures this week to boost the investment climate, employment and fiscal sustainability in one of the weakest European Union economies.

A snap election would delay those efforts and could have a negative impact on Croatia’s standing in the financial markets.