Prime Minister Nawaz Sharif resigned Friday following a Supreme Court judgement against him over his involvement in the Panama Papers scandal.
Sharif's spokesman announced his resignation shortly after the court disqualified him from office for life.
Attorney General Ashtar Ausaf told reporters that Sharif could not appeal the court's decision but he can file a petition for a review.
Sharif was convicted of financial irregularities, misuse of authority and concealment of assets relating to offshore companies and multi-million dollar properties tied to family members.
The judgement, which came after a 273-day hearing that gripped the nation, also bars Sharif from holding the leadership of the ruling Pakistan Muslim League.
The National Assembly is likely to meet in the coming days to select a new premier.
Meanwhile, a spokesman for the Prime Minister's Office said the government had "serious reservations" about the judgment and the conduct of the court.
He said Sharif had stood down "as per his promise" to do so if ruled against by the court.
INVESTIGATION
Earlier, the five-member bench of the apex court unanimously disqualified the premier for life, barring him from taking part in politics.
In its ruling, the court ordered the National Accountability Bureau, the country's anti-corruption authority, to file corruption cases against Sharif and his family within the next six weeks.
The judges disqualified Sharif after considering the report of a six-member joint investigation team, which was formed in April to look into the scandal.
The team submitted its report on July 10.
Investigators, including members of the country's two top spy agencies -- the Inter-Services Intelligence and the Military Intelligence -- had questioned Sharif's children, his son-in-law, brother and Chief Minister of Punjab province Shehbaz Sharif, as well as two close aides.
The Supreme Court also ruled that the Prime Minister had not fulfilled Articles 62 and 63 of the constitution, which say any public office holder shall be honest and truthful.
It is the third time Sharif has been ousted before completing his five-year tenure as prime minister. His two previous governments were dismissed over corruption charges and through a bloodless military coup in 1992 and 1999 respectively.
The court ordered the Election Commission of Pakistan to immediately issue a notification to de-seat Sharif from the National Assembly and directed President Mamnoon Hussain to summon the assembly to elect a new prime minister.
Information Minister Maryam Aurungzeb said that she was disappointed by the court's judgment, though it was not surprising to her.
SUCCESSOR
"No matter who will be the next prime minister… Nawaz Sharif will remain the prime minister in the hearts of the people of Pakistan," she said.
"The people of Pakistan would re-elect Sharif as prime minister for the fourth term."
She declined repeated questions about Sharif's successor, saying the party would discuss the issue after going over the court judgment.
Last year, Sharif faced immense pressure from the opposition and the media after the Panama Papers were leaked.
The papers revealed that his two sons -- Hassan Nawaz and Hussain Nawaz -- and daughter Maryam Nawaz owned offshore companies and properties worth millions of dollars, including luxurious apartments in London.
In April 2016, Sharif's eldest son, Hussain, admitted in an interview with a local broadcaster that his family owned offshore companies and overseas property.
He insisted the transactions were all legal and refused to make his assets public, claiming that such a move could harm his business interests.
Three months ago, the Supreme Court decided not to disqualify Sharif from office but ordered a further probe into the business activities of his children.
The judges had expressed dissatisfaction with the money trail provided by Sharif's lawyers and pointed out the failure of the country's top anti-corruption bodies in investigating the scandal.
'HARASSING FAMILIES'
Sharif's right-wing Pakistan Muslim League, which won the 2013 elections with a landslide majority, had accused the joint investigation team of pressuring witnesses.
The investigators denied the charge. They accused the government of hampering their inquiry and harassing their families.
Opposition parties welcomed the judgement as a "good omen" for democracy and the rule of law.
"Today is the victory day for the people of Pakistan," Siraj ul Haq, chief of Jamat-e-Islami, the country's largest Islamic party and one of the petitioners against Sharif, told reporters outside the Supreme Court.
"But this is just a beginning. The accountability process must not stop here. All other politicians, bureaucrats, businessmen and others whose names are in the Panama papers must be held accountable as well."
Tehrik-e-Insaf Vice Chairman Shah Mahmood Qureshi also welcomed the judgment.
The Panama Papers, released by the Washington-based International Consortium of Investigative Journalists in April 2016, pointed fingers at 140 politicians worldwide, including 11 current and former national leaders.
The investigation claimed they worked with the firm Mossack Fonseca to establish shadow companies for global transactions and money laundering.
Their revelation sent shockwaves across the world, resulting in the resignation of Iceland's Premier Sigmundur David Gunnlaugsson and political pressure on then British Prime Minister David Cameron, who later admitted to having a profitable stake in a fund owned by his father.
