Pakistan's Prime Minister Nawaz Sharif resigned Friday, after the country's apex court disqualified him for being "not honest" about his wealthy family's overseas assets revealed by the leaked Panama Papers.

The Prime Minister's Office issued a notification saying Sharif, who had been prime minister since May 2013, stepped down despite having "strong reservations" on the Supreme Court's verdict, which a spokesman for his political party said will be contested.

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The court dismissed Sharif after an anticorruption panel that investigated his family's offshore companies and assets recommended on July 10 that cases be initiated against him and his children in an anticorruption court.

Political parties and individuals had lodged five petitions seeking his disqualification on grounds that he failed to disclose his assets abroad in his income tax returns and lied in parliament on how they were acquired.

The Panama Papers leaked last year revealed that Sharif's three children -- sons Hassan and Hussain and daughter Maryam -- owned offshore companies incorporated in Panama and the British Virgin Islands and properties in London.

The judgment of the five-member Supreme Court bench, read out by Justice Ejaz Afzal, said Sharif "is disqualified to be a member of the Majlis-e-Shoora (Parliament)" and immediately after being notified as such, "he shall cease to be the Prime Mister of Pakistan."

It declared that Sharif was "not honest" since he "failed to disclose his un-withdrawn receivables constituting assets" from a Dubai-based company in his nomination papers filed for the 2013 general election and "furnished a false declaration under solemn affirmation."

It called upon Pakistani President Mamnoon Hussain, whose position is largely ceremonial, "to take all necessary steps under the Constitution to ensure continuation of the democratic process."

It is unclear at the moment who will take over as interim prime minister until the next general election, scheduled for 2018, but the president is expected to call upon a member of the National Assembly to do so with majority support in the assembly.

The court also ordered the National Accountability Bureau to initiate cases against Sharif and his children relating to their overseas properties. It said an anticorruption court working under the bureau should decide these cases within six months.

A spokesman for Sharif's political party, the Pakistan Muslim League (N), expressed confidence that he will eventually "triumph" in the court of public opinion, in an apparent suggestion that the three-time prime minister may again stand for election.

Observers say the court's disqualification of Sharif, whose previous two five-year terms also ended early, could trigger a war of succession in his party.

It was perhaps in an anticipation of such that Interior Minister Chaudhry Nisar Ali announced Thursday that he would resign from the Cabinet immediately after Friday's verdict.