Pakistan's president has dissolved parliament - a step towards early elections - following an attempt to remove PM Imran Khan from office.
Prime Minister of Pakistan Imran Khan (second from right) at a rally in Islamabad in support of his ruling PTI party. Photo: AFP/ Anadolu Agency
It comes after parliament's deputy speaker refused to hold a vote of no-confidence the PM was expected to lose.
Khan claims the US is leading a conspiracy to remove him because of his criticism of US policy and other foreign policy decisions he has taken.
Opposition politicians ridicule the allegation, and the US has denied it.
Imran Khan visited Moscow to meet President Vladimir Putin as Russia was launching the invasion of Ukraine, He has previously criticised America's "War on Terror".
The BBC's Secunder Kermani says the prime minister is widely regarded as having come to power with the help of Pakistan's army, but now observers say they have fallen out.
Supporters of the government of Pakistan and Prime Minister Imran Khan staged demonstrations in the capital Islamabad. Photo: AFP/ Anadolu Agency
His political opponents seized the opportunity to demand the no-confidence vote after persuading a number of his coalition partners to defect to them.
On Sunday, Information Minister Fawad Chaudhry told MPs that Pakistani officials had been told of "an operation for a regime change by a foreign government".
This, he said, went against the constitution and the deputy speaker chairing the session - a close ally of the prime minister - proceeded to declare the vote unconstitutional.
The opposition are furious.
"The united opposition is not leaving Parliament. Our lawyers are on their way to Supreme Court. We call on ALL institutions to protect, uphold, defend and implement the Constitution of Pakistan," chairman of the opposition Pakistan People's Party Bilawal-Bhutto Zardari tweeted.
Imran Khan, elected in July 2018 vowing to tackle corruption and fix the economy, remains popular with some voters, even though a lot of his public support has been lost as a result of rocketing inflation and ballooning foreign debt.
Last October, Khan refused to sign off on the appointment of a new chief of Pakistan's powerful ISI intelligence agency.
In public, however, both the military and Khan deny there has been any falling out.
There have been only two previous instances in Pakistan's political history when sitting prime ministers faced a vote of no confidence, and both times Benazir Bhutto, in 1989, and Shaukat Aziz, in 2006, emerged unscathed.
It is unclear how the current impasse will be resolved.
Heavy security has been deployed around government buildings and across the capital, Islamabad.
- BBC