The Pakistan People's Party (PPP), the nation's ruling party has "accepted" a Supreme Court order that has disqualified Yusuf Raza Gilani from his post as the prime minister of Pakistan.
Asif Ali Zardari, Pakistan's president, has held emergency talks among top leaders in the ruling PPP following Tuesday's disqualification.
The decision comes two months after Gilani, the nation's longest-running prime minister, was convicted of contempt for refusing to ask Swiss authorities to reopen corruption cases against President Asif Ali Zardari, state TV has reported.
"Yusuf Raza Gilani has become disqualified from being member of the parliament," said chief justice Iftikhar Muhammad Chaudhry, reading the order.
"He has also ceased to be the prime minister of Pakistan with effect from the same date [April 26] and office of the prime minister shall be deemed to be vacant accordingly."
The high court ordered Zardari to take steps to elect a new prime minister, state media reported.
The court has asked the president to "honour democracy and appoint a new prime minister as quickly" as he can.
Gilani, the nation's first-ever sitting prime minister to be convicted, can have the verdict reviewed but has no formal appeal process available to him, Al Jazeera's Imtiaz Tyab reported from Islamabad.
"It's going to be very difficult for [Gilani] to come back from this," our correspondent said.
"This is bad news for the president … In many ways Yusuf Raza Gilani was the president's biggest supporter, now this case [Gilani's] goes back to a case involving the president in 2008, when the supreme court ordered Yusuf Raza Gilani to write to the Swiss authorities to begin a corruption [investigation]."
Any decisions Gilani has made since that April 26 contempt of court declaration will be rendered invalid. In that time, Gilani has made several decisions, including on the national budget.
On February 13, the nation's top court summoned Gilani to charge him with contempt of court over his refusal to ask Switzerland to investigate Zardari, who is also the head of the ruling Pakistan People Party, for money laundering.
Gilani told the court he would never think of violating judicial orders, but said he could not write the letter because the head of state he enjoyed immunity under the constitution.
The court's April decision has been considered controversial.
Chief Justice Iftikhar Muhammad Chaudhry has been accused of working to bring down the current administration before February 2013, when it would become the first in Pakistan to complete a full five-year term in office.
The matter of disqualification fell first to the speaker of parliament, Fehmida Mirza, a member of the main ruling Pakistan People's Party, who on May 24 said conviction for contempt was not a charge that meant Gilani should be disqualified under the constitution.
Gilani subsequently decided not to appeal his conviction in a move interpreted as an effort not to antagonise the court into disqualifying him.
But senior opposition politicians, including cricket legend Imran Khan and former prime minister Nawaz Sharif, challenged the ruling.
The allegations against Zardari date back to the 1990s, when he and his late wife, former president Benazir Bhutto, are suspected of using Swiss bank accounts to launder an estimated $12m allegedly paid in bribes by companies seeking customs inspection contracts.
The Swiss shelved the cases in 2008 when Zardari became president.
Gilani has always insisted Zardari has full immunity as head of state and last month said that writing to the Swiss would be a violation of the constitution.
He was briefly, but symbolically, held in the courtroom for his sentence, which ended as soon as the judges arose for the day after announcing the verdict.