Mahathir Mohamad brushed aside doubts on Thursday that he would become Malaysia's next prime minister following his shock election victory over the coalition that has ruled the Southeast Asian nation for six decades since independence from Britain.
"There is an urgency here, we need to form the government now, today," Mahathir told a news conference, where he insisted that he would be sworn in as prime minister later on Thursday.
Malaysia's constitutional monarch has granted Mahathir an audience at 5:00 p.m. (0900 GMT), a leader of his Pakatan Harapan (Alliance of Hope) told Reuters.
Mahathir ruled Malaysia with an iron fist from 1981 to 2003 and now, at the age of 92, is set to become the oldest elected leader in the world.
His alliance of four parties trounced the Barisan Nasional (BN) coalition of Prime Minister Najib Razak, who was once Mahathir's mentor but became his most bitter rival.
Earlier on Thursday, Najib appeared to raise doubts that Mahathir would immediately take office because no single party had won a simple majority of seats in the 222-member parliament, and it would be up to the monarch to decide.
Official results showed that Mahathir's coalition won 113 seats, one more than the number required to rule. But it has not been formally registered as an alliance.
In jubilant mood and cracking jokes, Mahathir said he had been assured of support from a raft of parties that would give his government 135 members of parliament.
Najib's BN won 79 seats, a collapse from the 133 it won in the 2013 election, which was itself the coalition's worst poll performance ever at the time.
Few had expected Mahathir to prevail against a coalition that has long relied on the support of the country's ethnic-Malay majority.
However, he joined hands with jailed political leader Anwar Ibrahim, his one-time deputy he famously fell out with in 1998, and together their alliance exploited public disenchantment over the cost of living and a multi-billion-dollar scandal that has dogged Najib since 2015.
Mahathir said that one of his first actions would be to seek a royal pardon for Anwar. Before the poll he had promised to step aside once Anwar was free and let him become prime minister.
His wife, Wan Azizah Wan Ismail, was sitting next to Mahathir at the news conference. Under an agreement with Mahathir, she is to be deputy prime minister.
Anwar was imprisoned, first by Mahathir on charges of corruption and sodomy. He was released in 2004 but jailed again by Najib in 2015.
This week's stunning election outcome is expected to ruffle financial markets that had been expecting a comfortable win for Najib and the BN.
Malaysia's currency weakened in offshore trading on Thursday, with the ringgit one-month non-deliverable forward falling 1.2 pct. The U.S.-traded iShares MSCI Malaysia ETF fell 6 percent.
The national stock market was closed on Thursday and Friday after Mahathir declared a public holiday, but the ringgit currency weakened in offshore trading.
Mahathir repeated a promise to repeal a goods and services tax (GST) introduced by Najib and review foreign investments, including major infrastructure projects that are part of China's Belt and Road initiative.
Global ratings agency Moody's said some of his campaign promises, including scrapping GST and a reintroduction of fuel subsidies, could be credit-negative for Malaysia's sovereign debt rating.
Mahathir was once Najib's patron but they clashed over a scandal around 1Malaysia Development Berhad (1MDB), a state fund from which billions of dollars were allegedly siphoned off.
The 1MDB affair is being investigated by at least six countries, although Najib has denied any wrongdoing and has been cleared by Malaysia's attorney-general.
Mahathir had vowed to investigate the scandal if elected and bring missing funds back to Malaysia. On Thursday he said that if Najib had done anything wrong he would "face the consequences".