Pakistan Prime Minister Nawaz Sharif has been summoned by investigators probing the assets of the premier's family disclosed in Panama Papers, a Prime Minister house official confirmed on Sunday.

In recent weeks, Mr. Sharif's two sons Hussain Nawaz and Hassan Nawaz have been grilled for hours by the Joint Investigation Team comprising financial experts and representatives of intelligence agencies. The investigators have been ordered to probe the Prime Minister and his family whether they bought expensive flats in London through an off-shore account. Last year, Panama Papers revealed that the families who have hidden money from their authorities have purchased assets outside their countries.

JIT has been given two months by the Supreme Court to finish the probe. Thirty-five days have already been passed out of the sanctioned period. Mr. Sharif's government has accused some of the JIT members of having sympathies for the opposition political parties. The Supreme Court had rejected the objections and asked the JIT to continue its work.

In his defence, Prime Minister Nawaz Sharif told the Supreme Court that the flats were originally purchased by a Qatar-based firm in which they had invested, later the flats were transferred to his son Hussain Nawaz in 2000.

The Supreme Court had taken up the case last year and in its judgment held that an investigation team should probe the money trail after the Prime Minister's family failed to produce a clear money trail to establish amassing of assets abroad. Two out of the five judges of the apex court had already declared Prime Minister Sharif as not being truthful.

If JIT declares the Prime Minister guilty he can be dismissed and declared ineligible from politics forever. But ruling PML(N) leaders insist that the Prime Minister and his family will come out clean in the investigations.

The case was first highlighted in 1996 by a UK newspaper, which alleged that Nawaz Sharif laundered money to buy these four apartments in London's most expensive Park Lane area. A case was made against him but was shelved when he came back to power in 1997.