In a rare and explicit intervention in politics, the sultans of nine of Malaysia’s states have called for a swift and transparent investigation into a political scandal involving Prime Minister Najib Razak, saying his failure to resolve allegations of corruption had created a “crisis of confidence” in the country.

Malaysia’s central bank and anticorruption officials are investigating whether millions of dollars transferred into Mr. Najib’s accounts came from companies linked to a government fund that Mr. Najib oversees.

The statement by the sultans, who have a largely ceremonial role, was their most direct intervention in politics in recent history. Analysts said it was likely to provide support for the embattled officials who are investigating the scandal and buttress the position of the growing ranks of Mr. Najib’s political opponents.

… John Pang, a senior fellow at the S. Rajaratnam School of International Studies in Singapore, said Mr. Najib, who faces significant opposition in his party, now appears more isolated. “The statement adds to the sense that he has lost the confidence of the Malay rulers, along with other important sectors of society,” Mr. Pang said. The sultans, he said, “have never spoken so specifically on a matter of government.”

Their intervention “will embolden both the civil service and civil society groups that are dismayed by the scandal,” he said.