Pakistan's Supreme Court suspended the presidential appointment of two top judges in an emergency ruling that could cause a destabilizing clash between the judiciary and the unpopular, Western-backed government.

As local media reported the country was headed into a political and judicial crisis following the decision, President Asif Ali Zardari's spokesman issued a statement dismissing rumors the government was planning to declare a state of emergency.

The development will concern Pakistan's Western allies who want the country to concentrate on battling al-Qaida and Taliban militants in the northwest. The stability of the nuclear-armed nation is also key to Washington's hopes of defeating the insurgency just across the border in Afghanistan.

Zardari is already facing the prospect of legal challenges to his rule after the Supreme Court struck down an amnesty in December that had been shielding him from graft allegations dating back to the 1980s. Earlier last year, he was forced to reinstate the Supreme Court chief justice fired by former President Gen. Pervez Musharraf after demonstrations exposed his political vulnerability and the clout of the judiciary.

Saturday's ruling came after Zardari appointed a new Supreme Court judge and chief of the Lahore High Court, going against the recommendation of the Supreme Court. Pakistan's constitution says the president must consult with the Supreme Court over the appointment of new judges.

The court order said no consultation had taken place and the appointment "appeared to be in violation of the provision of the constitution."

Deputy Attorney General of Pakistan Shah Khawar said officials were summoned to appear Thursday to explain why the order had been issued against the court's recommendations.

Some TV channels quoted government critics as saying the appointment of the judges could be used as the basis for a fresh challenge against Zardari's hold on the presidency.

Information Minister Qamar Zaman Kaira said the president issued the order only after consulting the chief justice. "We have always acted constitutionally. We will take any step in future as required by the law and constitution."

Pakistan' lawyers and judges have always played a role in the political life of the country. Protests by lawyers were credited with helping oust Musharraf.

While undertaking operations against militants in the northwest, the Zardari government had been widely criticized for failing to make a dent in the country's major economic and social problems. Elements within the military are also believed to be angry at him for being too close to the United States and longtime foe India.