Lawyers for Pakistani Prime Minister Imran Khan began their defense in the Supreme Court on Wednesday of his bid to block an opposition attempt to oust him, a move his critics say was unconstitutional and has ushered in political turmoil.

Khan, a former cricket star, lost his parliamentary majority last week and had been facing a no-confidence vote tabled by the opposition that he was expected to lose on Sunday.

But the deputy speaker of parliament, a member of Khan's party, threw out the motion, ruling it was part of a foreign conspiracy and unconstitutional. Khan then dissolved parliament.

The standoff has thrown the nuclear-armed country of 220 million people, ruled by the military for extended periods since independence in 1947, into a full-blown constitutional crisis.

The opposition has challenged the decision to block the vote in the Supreme Court, which began deliberating the case on Monday.

On Wednesday, lawyers for Khan's Pakistan Tehreek-e-Insaf party began their defense.

The Supreme Court panel of five judges has not said when it will give a ruling. It could order parliament be reconstituted, call for fresh elections or bar Khan from power if he is found to have violated the constitution.

It could also decide that it cannot intervene in parliamentary affairs.

Pakistan's military is facing growing opposition calls to weigh in on the legitimacy of Khan's complaints about a foreign plot against him, which he said was being orchestrated by the United States.

The United States dismissed the accusation.

Khan, like many Pakistanis, criticized the U.S. intervention in neighboring Afghanistan, which came to an end with the withdrawal of U.S.-led foreign forces and the return of the Taliban last year.

A senior leader of the opposition, Maryam Nawaz, said the military should publicly clarify if it had told a top-level security meeting that the United States had conspired with the opposition to topple his government, as Khan has said it did.

"Imran Khan has used the National Security Committee for his political gains," she said late on Tuesday.

An official with knowledge of the matter, who declined to be identified, told Reuters on Tuesday that security agencies had not found credible evidence to confirm Khan's complaint of a conspiracy.

The Pakistan military's public relations wing and Khan's former information minister, Fawad Chaudhry, did not respond to requests from Reuters for comment on the matter.

The military has stepped in to remove civilian governments and take over on three occasions, citing the need to end political uncertainty, though the current military leadership says it is not involved in politics or in this situation.

As the court considers the legality of the political maneuvering, Khan's decision to dissolve parliament and call a general election is moving forward with President Arif Alvi asking the Election Commission to think about a date for a vote, which should be within 90 days of the April 3 dissolution.

"In order to carry out the mandate of the Constitution of announcing the date of general elections, consultation with the Election Commission is required," the president's office said.

But analysts say the process is not clear because a Supreme Court ruling against Khan would also throw into question his calling of a snap election.