Official campaigning began Monday for next month's South Korean presidential election to choose a successor to deposed President Park Geun-hye, with the election heavily tilted toward candidates from liberal parties following a corruption and cronyism scandal linked to Park.

A total of 15 candidates — a record number — are running for the presidency in the May 9 election after Park was arrested on March 31 after being ousted from office earlier that month. She still had one year of her five-year term left.

The two front-runners are Moon Jae-in of the Democratic Party of Korea, which has the most seats in the National Assembly, and Ahn Cheol-soo of the People's Party, the country's third-largest party.