AUCKLAND, NEW ZEALAND – The Pacific island nation of Samoa hurtled toward a constitutional crisis on Saturday, when the country's head of state announced that he was suspending Parliament just two days before it was scheduled to swear in the country's first new prime minister in more than two decades.

In a single-page letter posted to Facebook, Va'aletoa Sualauvi II, Samoa's appointed head of state, announced that Parliament would be suspended "until such time as to be announced and for reasons that I will make known in due course."

Samoa's Parliament had been scheduled to officially reopen on Monday, fulfilling a constitutional requirement to convene within a 45-day window of the April 9 election. Fiame Naomi Mata'afa, the leader of the newcomer party FAST, was to be sworn in as prime minister, ending Prime Minister Tuilaepa Aiono Sailele Malielegaoi's 22-year tenure.

Speaking by phone from Samoa early Sunday, Mata'afa said the proclamation was an attempt to prevent her party from taking power. "This is a coup," she said. Tuilaepa could not be reached for comment.

Mata'afa and her party, which campaigned on a platform of upholding the rule of law, have not yet given up hope of a legal resolution. Anticipating a roadblock before the proclamation was issued, the party's lawyers had prepared paperwork to challenge it. They want the country's Supreme Court to issue a ruling that would allow Parliament to convene on Monday as scheduled.

"They're going to have a meeting with the chief justice tomorrow," Mata'afa said. "We'll be filing for the revoking of this new proclamation."

It is unclear whether Sualauvi, whose role is ordinarily ceremonial, has the legal authority to suspend Parliament indefinitely or prevent it from meeting within the 45-day window.

A seasoned and well-liked politician, Mata'afa has been in politics for more than 30 years and is the daughter of Samoa's first prime minister. Her defection to FAST helped propel it to electoral success, eventually inspiring an influential independent candidate to throw his weight behind the party, breaking a tie.

"Everything about this election — people have talked about it being unprecedented, but now we're entering a truly unprecedented state," said Kerryn Baker, an expert on the region at the Australian National University. "Things could be sorted out through alternate channels, but we're essentially beyond the Constitution now."