Stopping short of admitting defeat, Najib said that the King will have to decide on the next Prime Minister, reports Efe news.
After the counting of votes, the EC confirmed a historic victory for the opposition, led by Mahathir, 92, which defeated the ruling coalition which had been in power since the country's independence.
Official results show that the opposition alliance Pakatan Harapan (Alliance of Hope) has won 113 of total 222 seats - crossing the required majority of 112 - while the ruling Barisan Nasional (National Front) managed to get just 79 seats.
The Malaysian Islamic Party (PAS) emerged as the third biggest force with 18 seats.
The EC published the first results in early hours of Thursday after not giving any information for many hours, while unofficial sources had started reporting the opposition's victory by Wednesday night.
In his first statement after victory, Mahathir told his supporters that his objective was to re-establish the rule of law after the corruption scandals that characterised Najib's term.
Mahathir, who was the longest-serving prime minister of the country between 1981-2003, was Najib's patron in the beginning of the latter's political career, but returned from retirement to defeat his former protege.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
