No prime minister has ever seen out a full term, and Khan is facing the biggest challenge to his rule since being elected in 2018, with opponents accusing him of economic mismanagement and foreign-policy bungling.
The government is also battling to contain a rise in militancy by the Tehreek-i-Taliban Pakistan (TTP), which on Wednesday announced an offensive against security forces during Ramadan, due to begin within days with the sighting of the next new moon.
Fighting for his political life, Khan addressed the nation late Thursday, appearing to blunder when he named the United States as the origin of a "message" he said showed meddling in Pakistan's affairs.
"America has -- oh, not America but a foreign country I can't name. I mean from a foreign country, we received a message," he said.
Local media reported the message was in a briefing letter from Pakistan's former ambassador to Washington, Asad Majeed Khan, recording a senior US official telling him they felt relations would be better if Khan left office.
"They say that 'our anger will vanish if Imran Khan loses this no-confidence vote'," he said.
