Pakistan’s embattled prime minister faces a no-confidence vote in Parliament on Sunday.

The opposition says it has the numbers to win after PM Imran Khan’s allies and partners in a fragile coalition abandoned him.

The opposition needs a simple majority of 172 votes in Pakistan’s 342-seat Parliament to unseat Khan, a cricketer-turned-politician.

His small but key coalition partners along with 17 of his own party members have joined the opposition to remove him.

The Parliament is scheduled to convene at 11:30am (06:30 GMT), but Pakistan’s parliamentary rules allow for three to seven days of debate. The opposition says it has the numbers for an immediate vote, but Khan’s party could force a delay.

On Sunday, giant metal containers blocked roads and entrances to the capital’s diplomatic enclave, Parliament and other sensitive government installations in the capital.

A defiant Khan called for supporters to stage demonstrations countrywide to protest against the vote.

The PM has accused the opposition of being in cahoots with the United States to unseat him, saying the US wants him gone over his foreign policy choices that often favour China and Russia.

Khan has also been a strident opponent of the US’s so-called "war on terror” and Pakistan’s partnership in that war with Washington.

Khan has circulated a memo that he insists provides proof that Washington conspired with Pakistan’s opposition to unseat him because the US wants "me, personally, gone … and everything would be forgiven”.

A loss for Khan would give his opponents the opportunity to form a new government and rule until elections, which are scheduled to be held next year.

The opposition could also choose to call early elections.

Pakistan’s main opposition parties, whose ideologies span the spectrum from left to right to religious, have been rallying for Khan’s removal almost since he was elected in 2018.

Khan’s win was mired in controversy amid widespread accusations that Pakistan’s powerful army helped his Pakistan Tehreek-e-Insaaf (PTI) party to an election win.

No prime minister has finished a full five-year term since independence from the United Kingdom in 1947, and generals on several occasions have ruled the country, which is perennially at odds with fellow nuclear-armed neighbour India.

Pakistan’s military has directly ruled Pakistan for more than half of its 75-year history, overthrowing successive democratically elected governments.

The country’s most popular English language newspaper, the Dawn, has said Khan is "as good as gone”.

"How can I accept the result when the entire process is discredited?” Khan told foreign journalists at his office on Saturday. "Democracy functions on moral authority – what moral authority is left after this connivance?”

"The move to oust me is blatant interference in domestic politics by the United States,” he said, terming it an attempt at "regime change”.