Pakistan's newly elected lower house of parliament met for the first time on Thursday with freshly elected members taking oaths amid protests on the floor of the house by supporters of jailed former Prime Minister Imran Khan.

The Sunni Ittehad Council (SIC) party backed by Khan alleges that the Feb. 8 national election was rigged against them and has called for an audit of the polls. No single party won a majority.

Candidates backed by Khan won the most seats but the Pakistan Muslim League-Nawaz (PML-N) and Pakistan Peoples Party (PPP), have agreed to an alliance to form a coalition government.

"Who will save Pakistan? Imran Khan, Imran Khan," SIC members chanted as legislators, including the prime minister in waiting Shehbaz Sharif, signed the membership register of the National Assembly.

One SIC member held up a poster reading "Release Imran Khan" as he went up to the speaker's dais to sign.

SIC's Omar Ayub, Khan's candidate to be prime minister, told journalists the party would seek the release of the former cricket hero who was has been convicted in a string of cases and faces over a decade in jail.

The election for the prime minister will be held on Mar. 4, local broadcaster Geo News reported.

The session took place under tight security after earlier this week the inaugural session of the Khyber-Pakhtunkhwa provincial assembly, where Khan's supporters will form government, was marred by the pelting of some members with pens and slippers from the visitor galleries.

A note from the National Assembly's media wing said visitor passes for upper galleries had been cancelled due to security reasons.

Not all members of the 336-member house took the oath, with the apportioning of 70 reserved seats for women and minorities still pending adjudication by the Election Commission of Pakistan (ECP).

The commission will decide on allocating reserved seats to the SIC, which did not win any seats in the polls but was later joined by Khan's successful supporters, who had contested as independents. The ECP completed hearings on the matter on Wednesday but has yet to deliver a ruling.

Khan's party was barred from the polls for breaching electoral laws and independent candidates are not eligible for reserved seats.

The ECP decision will not affect the ability of Sharif's alliance to form the government, but extra seats will be critical to ensure the minority government remains comfortably placed to pass critical legislation, and also to contain SIC's opposition. (Reporting by Gibran Peshimam; Editing by Raju Gopalakrishnan)