Malaysia's ruling party, Barisan Nasional or BN, has won two parliamentary by-elections.
The wins strengthen Prime Minister Najib Razak's grip on the nation, despite ongoing graft allegations.
The Election Commission said the seats were won by wider majorities than the 2013 federal election.
Political analysts say Najib could likely call for snap polls because of the decisive win.
Najib said in a statement that former Prime Minister Mahathir Mohamad had "turned the elections into a referendum on my leadership."
BN won the seats in Sungai Besar and Kuala Kangsar, communities along Malaysia's west coast.
The vote for the seats came up after the incumbents were killed in a helicopter crash last month.
Najib has been facing scrutiny over the source of nearly $700 million that ended up in a personal, secure bank account through companies linked to the 1MDB sovereign wealth fund, which was initiated by Najib six years ago.
Najib has repeatedly denied any wrongdoing and the Malaysian attorney general has said the funds were a personal donation from Saudi Arabia's royal family.
But the scandal has led to probes in 10 countries - including Malaysia, Britain, the United States and Switzerland - over allegations of political donations, inaccurate disclosures, possible money laundering and embezzlement.