Politics in Malaysia returned to chaos on Monday as Prime Minister Mahathir Mohamad submitted his resignation to the country’s king.

The prime minister’s office confirmed the decision in a short statement, saying the resignation letter was sent at 1 p.m. local time (0500 UTC).

Minutes before the resignation, Mahathir’s Bersatu party confirmed it had pulled out a four-party alliance that unexpectedly ousted the government of former leader Najib Razak in 2018.

As part of the coalition deal, 94-year-old Mahathir had promised that his longtime arch-rival Anwar Ibrahim would succeed him as prime minister in a year or two.

However, rumors emerged at the weekend that the Bersatu party was trying to form a new government and thwart Ibrahim’s succession bid.