KUALA LUMPUR: Malaysia's new leader, Mahathir Mohamad, said he barred his scandal-tainted predecessor and his wife from leaving the country to prevent them from fleeing from possible prosecution over a massive corruption scandal.

A leaked flight manifesto showed that Najib Razak and his wife Rosmah Mansor were planning to leave on a private jet Saturday to Indonesia's capital, Jakarta, fueling rumors that he was bolting the country days after a shocking electoral defeat that ended his coalition's 60-year grip on power.

"There are a lot of complaints against him, all of which have to be investigated," Mahathir told a news conference. "We have to act quickly because we don't want to be saddled with extradition from other countries."

Mahathir said the investigations would take some time because investigators need to contact authorities in other countries and gather evidence. He has said Najib will "face the consequences" if any wrongdoing is found.

Najib said on social media that he was planning to take a short vacation to spend time with his family. The Immigration Department, which initially said there was no travel ban, later issued a statement that the former prime minister and his wife were blacklisted from leaving Malaysia.

Mahathir confirmed that he prevented Najib from departing. He said there was sufficient evidence to investigate Najib over the corruption scandal involving the 1MDB state fund that's being investigated in the United States and other countries. U.S. investigators say Najib's associates stole and laundered $4.5 billion from the fund, with some $700 million landing in Najib's bank account and around $30 million used to buy jewelry for his wife. Najib has denied any wrongdoing.

Najib responded swiftly, saying he respects the Immigration Department's ruling and will remain in the country with his family. He also said he was committed to "facilitating a smooth transfer of power."

Later Saturday, Najib told a news conference that he was stepping down as president of the United Malays National Organization and as chairman of the National Front coalition to take responsibility for Wednesday's election debacle. The announcement came after strong calls emerged from the UMNO, the linchpin of the coalition, for Najib to resign.

Najib, 64, said his deputy, Ahmad Zahid Hamidi, would take over as UMNO president.

"We accept the people's verdict with an open heart," Najib said. "Maybe this will be an opportunity for us to fix our weaknesses and shortcomings, although these are more a matter of perception than reality. God willing, UMNO will continue to live."

The National Front, which has ruled Malaysia since independence from Britain, won only 79 of the 222 parliamentary seats, losing power to Mahathir's four-party alliance amid public anger over the 1MDB scandal and a rising cost of living.

It was a remarkable comeback for the 92-year-old Mahathir, who was prime minister for 22 years until his retirement in 2003. Angered over the 1MDB scandal, Mahathir had teamed up with former foes, including jailed opposition icon Anwar Ibrahim, to oust Najib.

Mahathir said Malaysia's king had agreed to pardon Anwar, who was jailed in 2015 for sodomy in a conviction that he said was politically motivated. Anwar's daughter Nurul Izzah told The Associated Press that her father, whose sentence ends June 8, would be released on Tuesday.

Also Saturday, Mahathir appointed Lim Guan Eng, an ethnic Chinese, as finance minister, the first ethnic minority to be appointed to the powerful post in 44 years.

Since 1974, the finance minister had been a Muslim Malay. The appointment of Lim, a chartered accountant who led the wealthy northern state of Penang since 2008, reflects reforms pledged by Mahathir's alliance to heal racial divisions in the country blamed on decades-old preferential policies.

Mahathir also named former Deputy Prime Minister Muhyiddin Yassin as home affairs minister and Mohamad Sabu as defense minister. All three appointees are party leaders in his alliance.

Mahathir said he would name the rest of his 25-member Cabinet this coming week.