FACTBOX-How do national elections in Pakistan work?

Independent candidates have the option to join any party after the elections. - Once constituted, the National Assembly holds a parliamentary vote to select a leader of the house, who becomes the prime minister.

Pakistan goes to the polls on Thursday in a widely watched national election that will lead to the formation of a new government to lead the crisis-ridden South Asian nation for the next five years.

Here are some facts about how the electoral system works in Pakistan: - Pakistan is a parliamentary democracy and voting will take place for seats in the federal legislature, called the National Assembly, and four provincial, or state, legislatures.

- 128 million Pakistanis out of a population of 241 million are eligible to vote - all those above 18. Polling booths are open from 9 a.m. to 5 p.m. (0400 GMT to 1200 GMT) usually but time can be extended in exceptional individual circumstances. - On election day, voters will cast their ballots for two legislators to represent their constituency - one federally and the other provincially. There are 5,121 candidates contesting for the federal legislature and 12,695 for the provinces.

- The National Assembly consists of 336 seats - 266 are decided through direct voting on polling day, while 70 reserved seats - 60 for women and 10 for non-Muslims - are allotted according to the strength of each party in the house. - Victorious candidates become members of the National Assembly. Independent candidates have the option to join any party after the elections.

- Once constituted, the National Assembly holds a parliamentary vote to select a leader of the house, who becomes the prime minister. - A successful candidate must show a simple majority in the house - that is, the support of at least 169 members.

- Once a prime ministerial candidate wins the vote in the National Assembly, they are sworn in as prime minister. The new prime minister picks cabinet ministers, who form the federal government. - A similar process is followed at the provincial level to pick a chief minister and a provincial government.