"Pakistan became an independent state in 1947; but the freedom struggle begins again today against a foreign conspiracy of regime change. It is always the people of the country who defend their sovereignty & democracy," Khan tweeted.

The opposition parties, who jointly unseated Imran Khan as prime minister of Pakistan in a midnight no-confidence vote, jointly nominated Shehbaz Sharif of Pakistan Muslim League-Nawaz as the new PM, said a report by Pakistan's ARY News.

Shehbaz Sharif is the brother of former Pakistan Prime Minister Nawaz Sharif, who is currently in the UK. According to media reports, Nawaz Sharif's party worked under his supervision to bring the opposition together against Imran Khan and have as many as 20 lawmakers of Imran Khan's party side with them.

Taking to Twitter, the chief of the Pakistan Muslim League (Nawaz) party, said, "Special thanks to media, civil society, lawyers, my Quaid Nawaz Sharif, Asif Zardari, Maulana Fazal-ur-Rehman, Bilawal Bhutto, Khalid Maqbool, Khalid Magsi, Mosin Dawar, Ali Wazir, Amir Haider Hoti & leaders & workers of all political parties for standing up for the Constitution!"

Pakistan People's Party chief Bilawal Bhutto is expected to be appointed as the next foreign minister in the new government, a local media report was cited by the news agency PTI.

"According to rumours, Bilawal Bhutto-Zardari is likely to be appointed as the Minister of Foreign Affairs,” GeoNews report said.

The National Assembly will reconvene on Monday to nominate the next PM, media reports said, adding that the nominations were to be filed by 2 pm today.