A meeting of senior leaders of four parliamentary parties — PML-N, MMA, PPP and ANP — was held in Islamabad on Monday, during which they agreed on formulating a joint parliamentary strategy to counter PTI's emergence as the most powerful party in the National Assembly.

Talking to media persons following the meeting, former prime minister Yousuf Raza Gilani said it has been decided that the agitating parties will “form a strong opposition both inside and outside parliament”.

The parties also reiterated claims that the recently-held elections were massively rigged.

Gilani denounced the interference of “non-state elements” and also criticised the alleged self-imposed censorship by media houses while reporting election-related protests.

Senior PML-N leader Raja Zafrul Haq, also present, alleged that the Election Commission of Pakistan had "remained ineffective" in the conduct of the election and demanded that the Chief Election Commissioner tender his resignation.

MMA chief Fazalur Rehman said those institutions "which stole the mandate of people" should be "ashamed" of themselves.

He also talked about a joint strategy, saying that all parties are deliberating on the issue to reach a consensus regarding a future course of action.

“We have unanimously rejected the election results. Now, we want to adopt a unanimous approach for a future course of action,” Fazal said.

The multi-party alliance had earlier announced that a joint protest would be launched against alleged "rigging" and "massive irregularities" in the polls and demanded a "transparent re-election".

“We have given sacrifices for democracy. We will not allow the establishment to hold this democracy hostage. We will fight for the independence of democracy," Fazal had said last week while talking to media persons following a multi-party conference on Friday.

Dawn had earlier reported that PML-N and PPP are set to play an ARD-like opposition role in parliament as they have agreed on formulation of a “coordinated joint strategy” if the PTI manages to form its government at the Centre.

The broad-based understanding on cooperation was reached during the first direct meeting between the leaders of the PML-N and PPP after the July 25 general elections on Sunday.

However, Jamaat-i-Islami (JI) chief Sirajul Haq said that the new government, likely of the PTI, should be given a chance to play their due role.

The JI emir, while addressing a press conference in Lahore, struck a contrasting tone to that of his fellow MMA leader Fazalur Rehman, who rejected the result of the July 25 elections and floated the idea of not taking oath and may even push for fresh polls.