Pakistan's Prime Minister Imran Khan said his government handed an official protest to the U.S. embassy on Friday over what it called Washington's interference in the country's affairs.
"We now have given a demarche to (the) American embassy," Khan told local television channel ARY in an interview, referring to a diplomatic note over what he described as a foreign conspiracy to oust him from power.
Faced with a tight no-confidence vote on Sunday that could see him ousted after defections from his ruling coalition, Khan had said on Thursday that a foreign country was conspiring against him after he visited Moscow in February.
Khan met Russian President Vladimir Putin in Moscow on the day Russian forces invaded neighbouring Ukraine.
Speaking on Thursday in a nationally televised address, Khan said a Western country had been unhappy about his Moscow visit. He mentioned the United States before smilingly correcting it to "a foreign country".
But on Friday evening Khan named the United States, in his interview with ARY News TV.
The White House denied the United States had been seeking to remove Khan from power.
The U.S. embassy in Islamabad did not immediately reply to a request for comment.
Ruling party members in Pakistan led a protest against the United States in the northwestern city of Peshawar on Friday.
In an unusual move, dozens of Pakistan Tehreek-e-Insaf (PTI) ruling party figures, led by a provincial minister, rallied in the centre of Peshawar, chanting "Down with America!"
"We have come out to support Imran Khan who has challenged the capitalist forces," the minister, Taimur Jhagra, told the rally. "We will prefer hunger over a surrender to the U.S.," said another provincial lawmaker in the rally, Fazal Elahi.
A handful of activists from an anti-America Shi'ite group also reacted to Khan's claims, holding a rally in Islamabad where they burned American flags.
Khan has said his government possessed an "official document" that was evidence of the conspiracy. The document was later described by the government as a formal communication of a "senior official of a foreign country to Pakistan's Ambassador in the said country in a formal meeting".
(Reprting by Asif Shahzad in Islamabad and Jibran Ahmad in Peshawar, Editing by William Maclean)
