Islamabad, Mar 3 (IANS): Polling for Pakistan's Senate were underway on Saturday in the national and provincial assemblies as 133 candidates contest for 52 seats.

The Senate - the Upper House of Parliament - is a body of 104 lawmakers. Each serves a term of six years, barring resignation, disqualification, or other extraordinary circumstances, reports Dawn news.

They are not all elected at the same time: rather, half are elected at one time, and the other half three years later.

In 2018, 52 senators (who were elected in 2012) are slated to retire. The other 52 were elected in 2015 and will retire in 2021.

Of the 52 Senate seats being vacated for the election, 46 will be filled by the four provincial assemblies, 2 by the National Assembly, and 4 by lawmakers representing the Federally Administered Tribal Areas (FATA).

Of all the candidates in the running, 20 are looking to secure one of 12 seats from Punjab, 33 are contesting for 12 seats from Sindh, 26 for 11 seats from Khyber Pakhtunkhwa, 25 for 11 seats from Balochistan, 24 for four seats from Fata and five for two seats from the federal capital.

According to a senior Election Commission of Pakistan official, Rangers and Frontier Corps personnel have been deployed outside all the polling stations established in Parliament House and the four provincial assemblies, Dawn news reported

Returning officers have been given magisterial power during the polling process that will continue from 9 a.m. till 4 p.m., without a break.

Media personnel have been barred from entering the provincial assemblies as well as the Parliament building as part of the security arrangements.