Islamabad, Pakistan (CNN) -- In a move that could reignite a political crisis in Pakistan, the nation's Supreme Court on Tuesday ruled that Prime Minister Yousuf Raza Gilani is ineligible to hold office.
The seven-member court declared the prime minister disqualified retroactive to April 26, the day he was convicted of contempt charges. Those stemmed from his refusal to call on Swiss authorities to reopen old corruption charges against Pakistani President Asif Ali Zardari.
"Since no appeal was filed against this judgment, the conviction has attained finality. Therefore, Syed Yousuf Gilani has become disqualified from being a member of the Majlis-e-Shoora (parliament)," according to the Supreme Court ruling, read in the court by Chief Justice Iftikhar Muhammad Chaudhry.
"He has also ceased to be the prime minister of Pakistan with effect from the said date (April 26), and office of the prime minister shall be deemed to be vacant accordingly."
It wasn't immediately clear if Gilani and the ruling Pakistan Peoples Party would appeal the decision and fight for the prime minister to remain in office. Political analyst Ahmed Mehboob told CNN the prime minister can appeal the court's ruling or the ruling party can begin selecting a replacement.
The speaker of Pakistan's National Assembly had 30 days from the day of the April verdict to ask the Election Commission to pursue disqualification proceedings if she viewed Gilani's conviction as cause for dismissal.
In a five-page decision released last month, Speaker Fahmida Mirza said she did not believe the prime minister's refusal to follow the Supreme Court's order justified disqualification. The speaker's ruling seemed to give a boost to the prime minister, who decided not to appeal the court's conviction.
The Supreme Court essentially overruled the speaker's decision Tuesday. The commission issued a "notification of disqualification" of Gilani after the order.
"The president of Pakistan is required to take necessary steps under the constitution to ensure continuation of the democratic process through the parliamentary system of government in the country," the Supreme Court order said.
Zardari postponed a trip to Russia and huddled with Pakistan Peoples Party senior leaders.
Federal information minister Qamar Zaman Kaira, speaking at a news conference, said the party has reservations about the verdict. Jehangir Badr, general secretary of the party, said that "technically" Gilani is no longer prime minister.
Kaira said senior members have decided that Zardari, also the party chairman, will make a final decision on how to proceed after he meets with coalition partners. A presidential pardon has not yet been discussed.
Pakistan has been beset by militant activity and political tumult for years. Fighters from the Taliban and al Qaeda use the northwestern territories as bases for attacks in Afghanistan, and U.S. drones regularly strike militant positions.
The United States and the Afghan government have been concerned that the warfare and instability could hurt the government.
But the crisis and a possible departure of the prime minister wouldn't have a seismic effect on the nation's stability and political system because the country's civilian government is dominated by the Pakistan Peoples Party.
A new prime minister would simply take the place of Gilani as a representative of the party. The current government is approaching the end of its term in February, the first time since the state was founded that an administration would complete a five-year term.
Journalists Nasir Habib and Ayza Omar contributed to this report.