KUALA LUMPUR, Malaysia — The Malaysian authorities said Najib Razak, the prime minister who was ousted in elections this week, and his wife were barred from leaving the country as a leaked flight plan stirred suspicion that they were planning to flee.
Mr. Najib faces possible investigation for corruption over billions of dollars he is accused of misappropriating from a state investment fund he once ran, including $731 million the United States Justice Department says was deposited in his accounts.
The Immigration Department of Malaysia said Saturday in a post on its Facebook page that Mr. Najib and his wife, Rosmah Mansor, had been placed on a blacklist that prevented them from leaving the country.
He wrote on social media that he had been told of the government order, and that he would respect the decision.
In a series of earlier messages Saturday, Mr. Najib said he apologized “for any shortcomings and mistakes, but did not address the scandal at the fund, 1Malaysia Development Berhad, known as 1MDB, directly in his Twitter post on Saturday.
He said that he planned to “take a short break to spend time with my family,” but did he not mention news reports that said he and his wife were planning to travel to Jakarta, Indonesia, citing to the leaked flight plan.
“I pray that after this divisive period, the country will unite,” he wrote as part of his posts on Twitter and Facebook. “I apologise for any shortcomings and mistakes, and I thank you, the people, for the opportunity to lead our great nation. It has been the honour of my lifetime to serve you and Malaysia.”
He has previously denied any wronging in connection with 1MDB.
Malaysiakini, a news website, quoted a source close to Mr. Najib who said the former prime minister and his wife planned to go to Jakarta for a two-day trip but would return.
A crowd of people and journalists gathered Saturday at Sultan Abdul Aziz Shah Airport, where the couple was apparently scheduled to depart on a private plane. Some of the crowd peered into arriving vehicles, but there was no indication Mr. Najib and his wife were there.
Mr. Mahathir, who previously served as prime minister from 1981 to 2003, said that any wrongdoing connected with 1MDB would be investigated, including whether the attorney general or anticorruption commission failed to fully pursue the allegations.
“Our intention is to go for people who have shown a tendency to be