KATHMANDU, Nepal (AP) — A key party pulled out of Nepal's ruling coalition on Monday, forcing the prime minister to seek a vote of confidence in Parliament.

Communist Party of Nepal (Unified Marxist Leninist), the biggest party in Prime Minister Pushpa Kamal Dahal's coalition, was angered by his decision to back an opposition candidate in next week's presidential election.

It is the third party to withdraw from the government since it was formed in December, after no party managed to secure a majority in the November parliamentary elections.

Political turmoil and frequent changes in government are nothing new in Nepal, where eight different governments have ruled in the past 10 years.

It was not clear if Dahal would manage to stay in power. The constitution says he would have to seek a vote of confidence within a month to secure support of the majority of the 275 members in the House of Representatives, the lower chamber of Parliament.

Dahal recently got the backing of the Nepali Congress party, the largest group in Parliament, after agreeing to back their candidate for president.