By Asif Shahzad and Gibran Naiyyar Peshimam
ISLAMABAD (Reuters) - Pakistani Prime Minister Imran Khan on Thursday rejected opposition calls for him to resign, and accused an unnamed Western country of backing moves to oust him because he had visited Moscow recently for talks with President Vladimir Putin.
Khan, 69, has faced mounting criticism of his performance, including his management of a troubled economy of the nuclear armed country. On Sunday, he faces a tough parliamentary no-confidence vote seeking to oust him from power.
"I have never accepted defeat in life. Whatever the result of the vote, I will come forward with more strength," Khan said in a nationally televised live address.
The vote has become increasingly difficult for Khan since he lost his majority in parliament when his main ally quit his coalition. It could see the former cricket star ousted and the return of political uncertainty.
Earlier on Thursday, opposition parties called on him to resign ahead of the parliamentary vote.
"I want to give you a suggestion that you take an honourable exit, and an honourable exit is that you resign today," opposition leader Bilawal Bhutto Zardari, son of assassinated former Prime Minister Benazir Bhutto, told reporters at parliament.
A parliamentary debate on the vote against Khan was set to begin on Thursday, but the speaker of the assembly, a member of Khan's party, immediately adjourned the session to Sunday.
Political analysts said Khan enjoyed the support of the military when he won an election to become prime minister in 2018 but he later lost the generals' favour over various wrangles.
Khan has denied ever having the backing of the military, and the military, which has ruled Pakistan for about half its history, denies involvement in civilian politics.
Khan in his address on Thursday said the move to oust him was a "foreign conspiracy" backed by a Western country that was unhappy with his visit last month to Moscow to meet Putin.
Khan was in Moscow and met with Putin the day Russian forces invaded neighbouring Ukraine.
Khan did not openly name the alleged conspiring country. He mentioned the United States before smilingly correcting it to "a foreign country".
He said his government possessed an "official document" that was evidence of the conspiracy.
"It (the document) says we will forgive Pakistan if Imran Khan loses this no-confidence vote. But if it fails Pakistan will have to face tough time," Khan said.
Before his speech, Khan summoned a National Security Committee (NSC) meeting to discuss the document, which was described as "the formal communication of a senior official of a foreign country to Pakistan’s Ambassador in the said country in a formal meeting".
An official statement after the NSC meeting said the gathering expressed grave concern at the communication.
The committee concluded the communication amounted to "blatant interference" in Pakistan's internal affairs, the NSC statement said, adding, it decided Pakistan will issue a strong demarche to the country.
(Reporting by Asif Shahzad and Gibran Peshimam in Islamabad and Syed Raza Hassan in Karachi; Writing by Alasdair Pal; Editing by Robert Birsel and Bill Berkrot)