Muhyiddin Yassin, a former deputy prime minister, took the oath of office on Sunday to become Malaysia's new prime minister.
Muhyiddin was appointed following the abrupt resignation of 94-year-old Mahathir Mohamad, who had been in office since the general elections in 2018.
Who is Muhyiddin Yassin?
TV live-broadcast showed that Muhyiddin, wearing traditional Malay clothes, pledged to serve the country and the people well before Malaysia's King Sultan Abdullah Sultan Ahmad Shah at the national palace.
The ceremony was attended by Muhyiddin's political allies.
The change in leadership came after a week of turmoil that followed the collapse of a reformist government and Mahathir's resignation as prime minister.
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The 94-year-old quit amid plans by his supporters in Bersatu party to team up with opposition parties to form a new government and thwart the transition of power to his named successor, Anwar Ibrahim.
Minutes before Mahathir tendered his resignation to the palace, Bersatu said it would leave the four-party Alliance of Hope and support Mahathir as prime minister. Eleven other lawmakers, including several Cabinet ministers, announced they were quitting Anwar's party to form an independent bloc.
Anwar, 72, was supposed to replace Mahathir before the next election, which is due in 2023, based on their alliance promise in the 2018 elections that Mahathir would one day cede power. Tension has persisted recently, with Anwar accusing Mahathir of "breaking his promise."
(With input from Xinhua, Reuters)