Ousted Malaysian Prime Minister Najib Razak said on Saturday that he and his family would respect an immigration department ban on his travel overseas and stay in the country.
Mahathir, the world's oldest elected leader, had retired as premier in 2003 after over two decades in the top job but staged a surprising comeback in a bid to oust his ex-protege Najib.
Mahathir has been prime minister earlier, for 22 years, governing in a tough, pugnacious style.
The new Malaysian government will review all foreign contracts and projects, including the Kuala Lumpur-Singapore High-Speed Rail project and those under China's Belt and Road initiative, Dr Mahathir said. He has denied any wrongdoing.
More details from Malaysian investigations into 1MDB could come to light with Mahathir at the helm, since roadblocks will likely now be less prominent, Pili said.
"If the party failed in the general election, the leader has the moral obligation to step aside".
On the 1MDB report, Dr Mahathir said he had instructed the Royal Malaysia Police to declassify the report under the Officials Secrets Act and it would then would be submitted to him for scrutiny and further action. "It is about making amends about his mistakes and moving Malaysia forward".
"I urge all UMNO members to unite and support the new leadership".
Anwar, whose sentence ends on June 8, should be free to participate in politics, he said. Lim Guan Eng, secretary-general of the Democratic Action Party, was appointed as the Finance Minister; Mohamad Sabu, a long-time opposition politician, as the defence minister; former deputy prime minister Muhyiddin Yassin, as the home or interior minister; former Central bank Governor Zeti Akhtar Aziz and business tycoon Robert Kuok were appointed as members of the "Council of Elders".
The lawmaker said a key reason for declaring the public holidays was so that Mahathir could announce key ministerial positions and name the new adviser before trading started on Monday in an effort to reassure global investors that his government was off to a solid start. Mahathir is being investigated under that law for claiming a plane he was to travel on was sabotaged during the campaign.
As it became clear that BN was facing a historic wipeout, Najib kept a low profile before surfacing Thursday morning to tell a press conference that he accepted the people's will, although he stopped short of conceding defeat.
The National Front "will honor the principle of democracy in the parliament", he said.
But calm returned to offshore trading of the ringgit currency, which lost four percent on Thursday.