​​​​​​​ISTANBUL

People in Thailand were voting Sunday in a snap general election and a nationwide constitutional referendum, a first in the country’s political history.

Polling stations opened at 8 am local time (0100 GMT), state broadcaster Thai PBS World reported.

More than 50 million eligible voters are choosing 500 lawmakers from about 5,000 candidates in elections for the House of Representatives. The vote follows the dissolution of the lower house on Dec. 12, a year before the end of its four-year term.

Of the 500 seats, 400 are being filled through constituency races, while the remaining 100 will be allocated to political parties on a proportional basis according to nationwide party-list votes.

The outcome will determine who forms the next government and whether caretaker Prime Minister Anutin Charnvirakul can retain power.

Sunday’s vote is widely described as a “three-in-one” poll, marking the first time in Thailand’s political history that voters are simultaneously electing lawmakers and taking part in a national referendum on whether to rewrite the 2017 military-era Constitution.

Each voter is receiving three ballots: a pink ballot for the party-list vote, a green ballot for constituency candidates and a yellow ballot for the constitutional referendum.

In the race for executive leadership, 19 political parties have nominated the maximum of three candidates for prime minister, while 12 parties have put forward two candidates each and another 12 have nominated one. The oldest candidate in the election is 90 years old.

Bangkok, the country’s most populous province, has the highest number of constituencies at 33, followed by Nakhon Ratchasima with 16. Khon Kaen and Ubon Ratchathani each have 11 constituencies.

Under election rules, official final results must be announced no later than April 9. The new parliament is required to convene within 15 days of the certification of results to elect a speaker. Once a speaker is chosen, the House of Representatives will then vote to select the next prime minister.

The election is seen as a contest among three major political forces: the Bhumjaithai Party, the People’s Party and the Pheu Thai Party.

Opinion polls indicate that no single party is likely to win enough seats to govern alone, making coalition-building necessary to form the next government.