A Pakistani court on Thursday extended former Prime Minister Imran Khan's pre-arrest bail for one week in a terrorism case over a speech, his lawyer said, shortly after the former premier appeared in court in person amidst tight security.

Khan's lawyer and political aide Babar Awan told Reuters bail had been granted until Sept. 1, after which they will apply for another extension. The former premier maintained after the hearing he had said nothing wrong in the speech last week.

Police filed charges on Saturday against former cricket star and national team captain Khan over what they said was a threat when he spoke about police torture of an aide who faces sedition charges for inciting mutiny in the military.

Political tensions in Pakistan remain high as Khan rallies support for elections that are not due until October next year. The former premier, who has attracted large crowds in gatherings across the country since being ousted in April, said his opponents were spooked by his popularity.

In his speech last week, Khan said he "would not spare" the Islamabad police chief and a female judge who remanded his aide to custody, adding he would take legal action against them.

Police cited that comment and said Khan's purpose was to spread terror amongst the police and the judiciary and prevent them from doing their duty.

Khan's bail in the matter was to expire on Thursday, but the court granted him one more week after his court appearance.

"We asked for a longer time because Imran Khan is contesting elections on many seats and he needs to go on campaign, but court gave us just a week," Awan told Reuters.

Khan's supporters and former ministers in his government have threatened mass protests if he is arrested. One former minister has said his supporters would "take over" Islamabad.

Speaking after the extension of his bail, Khan - surrounded by his aides and supporters - told reporters outside the court he had said nothing wrong.

"I say I will take legal action, and they make a terrorism case on me because of that, just think what mockery has been made of this internationally," he said.