Pakistan’s former prime minister Imran Khan will remain in a high-security prison for at least another two weeks despite being granted bail the previous day, as an anti-terrorism court extended his detention in a case involving the revealing of a secret document, a defence lawyer said.

The anti-terrorism court announced the decision after a closed-door hearing at the high-security Attock prison in the eastern Punjab province, Khan’s lawyer Intazar Hussain Panjutha said.

The next court hearing will be on September 2, he said.

Khan’s other lawyer, Salman Safdar, told reporters that he is petitioning a court to seek bail for the former leader in the latest case. He said he is challenging Khan’s imprisonment and trial as “it is illogical and unconstitutional”.

The latest development was a blow to Khan and his legal team, which expected his release after a court in the capital, Islamabad, suspended the corruption conviction and three-year prison term of the former premier.

Tuesday’s ruling by the Islamabad High Court, which also granted him bail, was a major legal victory for Khan. He has been held in prison since August 5, when he was arrested after his conviction and sentencing by another court.

Khan has been embroiled in more than 150 cases since his removal through a no-confidence vote in parliament in April 2022.

One of the key cases against him was registered by the Federal Investigation Agency earlier in August on charges of “exposing an official secret document”, which Khan had waved at a political rally in Islamabad after his removal.

In his televised speeches, Khan repeatedly described the document as proof of a threat to him from the United States.

The document, dubbed Cipher, has not been made public by the government but apparently contained diplomatic correspondence between the Pakistani ambassador to Washington and the ministry of foreign affairs in Islamabad.

Before his arrest, Khan publicly said his removal was a conspiracy by the United States, his successor Shehbaz Sharif, and the Pakistani military – accusations that they all deny. Mr Sharif stepped down on July 28 after the parliament’s term ended.

Khan’s continued detention will give an edge to his political rivals ahead of the vote to be held later in the year.

Pakistan’s election oversight body said that elections must be delayed for at least three to four months because it needs more time to redraw constituencies to reflect a recently held census.

It is widely believed that the vote will be delayed until February.

However, until then, caretaker Prime Minister Anwaar-ul-Haq Kakar is running the day-to-day affairs.