Pakistan's Prime Minister Imran Khan speaks during an interview with Reuters in Islamabad,
Pakistan recently struck a trade deal with Russia on wheat and gas imports despite increasing pressure from the west to condemn Russian aggression in Ukraine. In photo: Khan speaks during an interview with Reuters in Islamabad, Pakistan June 4, 2021. Reuters / SAIYNA BASHIR

Thousands of Pakistani opposition party supporters rallied on Tuesday to demand Prime Minister Imran Khan's ouster, accusing him of mismanaging the economy and poor governance, in the toughest challenge he has faced since taking power in 2018.

The opposition campaign, led by the Pakistan People's Party (PPP) of assassinated ex-prime minister Benazir Bhutto, raises the prospect of political turmoil in the nuclear-armed nation where the powerful military often determines who rules.

"Resign in 24 hours and face us in an election," Bhutto's son and PPP leader Bilawal Bhutto Zardari told the rally just outside the capital Islamabad, directing his comments at Khan.

"Or be prepared for a no-confidence move."

The opposition later submitted a formal request requiring Khan to seek a parliamentary vote of confidence. The opposition needs a simple majority of 172 and says it requires just 11 more votes to force Khan out in such a vote.

"We will have more than 172 votes," said Bilawal Bhutto's father Asif Ali Zardari, a former president of Pakistan.

The speaker of the lower house must now convene parliament within two weeks.

Opposition lawmakers and political analysts say Khan, a former cricket star, has lost the backing of the military whose support they say he obtained in order to win power for his upstart political party four years ago.

Khan denies the military helped him into power. The military says it has nothing to do with politics.

Opposition leaders say Khan has lost public support as he struggles with high inflation, a rising current account deficit and depleting foreign reserves.

Khan rejects that charge and has responded to economic problems with cuts in fuel and electricity prices, while rejecting calls to step down and warning the opposition of unspecified consequences if they force a vote of no-confidence.

Both the opposition and Khan's party are riven by factions.

Khan won a vote of confidence last year by six votes.

Pakistan's next general election is due by 2023.