The tussle between the Supreme Court and the civilian government in Pakistan escalated Friday, as the chief of the anti-corruption bureau rejected Chief Justice Iftikhar Muhammad Chaudhry’s order to arrest Prime Minister Raja Pervez Ashraf in a graft case.

On Tuesday, the Supreme Court ordered the arrest of the prime minister and 15 others in a graft case. Ashraf and the others allegedly accepted kickbacks on contracts when he was the power minister.

Fasih Bokhari, head of the National Accountability Bureau (NAB), told the Supreme Court Friday that the investigations against the prime minister were incomplete and there was no sufficient evidence to arrest the accused.

The investigating officers “were not able to bring incriminating evidence but relied on oral statements which are not warranted in the court of law,” Bokhari said, Press Trust of India reported. He sought more time to investigate the allegations against the prime minister.

Unimpressed by Bokhari’s argument, the court asked him to produce the case files so that the judges could determine whether there was sufficient evidence against the prime minister and others accused in the case, Reuters reported.

Bokhari’s decision has brought a temporary relief to the Pakistani government which was under pressure from different fronts.

The government is facing threats from a Muslim cleric who is spearheading a massive campaign demanding the electoral reforms and the ouster of the present government before the general elections due in May.

The fiery Sunni Muslim cleric, Muhammad Tahirul Qadri, who returned from Canada, has issued an ultimatum till 3:00 p.m. (local time) Friday to dissolve the parliament and to install a caretaker government in consultation with the military and judiciary to implement the reforms before the elections.

“Today is the last day of this sit-in. Tomorrow there will be no sit-in. We have to end it today," he said Thursday to his thousands of supporters who were camping near the federal parliament, according to the Times of India.

The timing of the protests has fueled speculations about a tacit arrangement between the military and the cleric to oust the civilian government. The military has a long history of political intervention and Qadri backed a military coup in 1999.

Political analysts believe that Qadri’s sudden arrival in the country from Canada and the Supreme Court’s arrest order against the prime minister suggest an elaborate design to pave the way for another military intervention in the election process.

No civilian government in Pakistan has completed its full term and the country was under military rule for more than half of its 65 years after independence.

However, both the Qadri and the military denied the allegations.

"It is totally incorrect to say the army is behind Qadri. But if he brings thousands of people to the streets and things get worse, there may be very few options," a senior military officer, who said he was speaking in a purely personal capacity, told Reuters.

The ruling Pakistan People’s Party and its allies held a meeting Thursday to discuss the political crisis, Geo News reported. The parties reportedly urged the government to hold talks with Qadri to ease the current crisis, and the latter constituted a 10-member committee for that purpose.