Pakistan’s Supreme Court on Thursday blocked Prime Minister Imran Khan’s bid to stay in power, ruling that his move to dissolve Parliament and call early elections was illegal. That set the stage for a no-confidence vote by opposition lawmakers, who say they have enough support to oust him.

The decision followed four days of hearings by the top court on the political crisis. Khan had tried to sidestep the no-confidence vote by accusing his political opponents of colluding with the United States to unseat him.

Lawmakers will probably convene Saturday for the vote, and the opposition says it has the 172 votes in the 342-seat house needed to oust Khan after several members of his own party and a key coalition partner defected.

“It's an unfortunate decision,” Khan's ally and Information Minister Fawad Chaudhry told The Associated Press following the unanimous ruling by the five-member Supreme Court. He warned that “instability will increase and I see no end to the crisis.”

Dozens of heavily armed police backed by paramilitary Rangers surrounded Pakistan’s stately white marble Supreme Court building. Roads leading to the court were blocked and a heavily armed contingent of police also encircled the nearby Parliamentary Lodges where opposition and government lawmakers stay when Parliament is in session.

Opposition leader Shahbaz Sharif, who heads the Pakistan Muslim League and is the likely candidate for prime minister if the no-confidence vote succeeds, welcomed the ruling as a victory for “justice and the supremacy of law.”

The political crisis began Sunday when an embattled Khan dissolved Parliament and set the stage for early elections. Chaudhry had stood in Parliament and accused the opposition of “disloyalty to the state” by working with a foreign power to bring about a “regime change.”

The deputy parliamentary speaker Qasim Suri cited Chaudhry's allegation to toss out the no-confidence resolution, but the Supreme Court ruled that Suri had no grounds to do so.

Chaudhry did not say what Khan's next step might be. Khan previously had called for nationwide demonstrations to protest what he called Washington's interference in Pakistan's affairs.

READ: Pakistan's top court rules against PM, restores Parliament

During the week, the Supreme Court heard arguments from Khan's lawyers, the opposition and the country’s president before handing down the decision Thursday night, after iftar, the meal that breaks the daylong fast during the Muslim holy month of Ramadan.

“This is the unfortunate fact about Pakistani politics — the political issues, which should be settled in the parliament are instead brought to the Supreme Court to settle,” said analyst Zahid Hussain, who has authored several books on militancy in the region and Islamabad’s complicated relationship with Washington.

“It is just a weakness of the system,” Hussain added.

Khan said the U.S. wants him gone because of what he describes as his independent foreign policy, which often favors China and Russia. He also has been a strident critic of Washington's war on terrorism and was criticized for a visit to Moscow on Feb. 24, hours after Russia invaded Ukraine.

The U.S. State Department has denied any involvement in Pakistan's internal politics.

"Khan tapped into a potent vein of anti-American sentiment in Pakistan that is unlikely to dissipate any time soon," said Elizabeth Threlkeld, Pakistan expert at the U.S.-based The Stimson Center. “Young people make up the majority in the country and grew up during the two-decades-long war on terror, which is deeply controversial in Pakistan.”

She warned the anti-U.S. rhetoric could further complicate Pakistan's relationship with Washington

Pakistan's top court or its powerful military have consistently stepped in whenever turmoil engulfs a democratically elected government. The army has seized power and ruled for more than half of Pakistan's 75-year history.

The military has remained quiet in the latest crisis, although army chief Gen. Qamar Javed Bajwa told a security summit in Islamabad last weekend that Pakistan wants good relations with China, a major investor, and also with the U.S., the country's largest export market.

“The ongoing constitutional crisis is a major test for Pakistan’s institutions, which stems from both tensions between the prime minister and the military and economic pressures that created an opening for the opposition,” Threlkeld said.

“While a serious challenge, this is also an opportunity for Pakistan’s institutions to demonstrate their resilience should they manage to restore a legitimate constitutional process,” she said.

The latest political chaos has spilled over into the country's largest province of Punjab, where 60% of Pakistan's 220 million people live and where Khan's ally for chief provincial minister was denied the post on Wednesday, after his political opponents elected their own candidate.