Imran Khan

Former Pakistan prime minister Imran Khan was on Wednesday remanded in jail over a leaked documents case, extending his detention despite the suspension of his prison term for graft a day earlier.

Khan has been tangled in a slew of legal cases he says are politically motivated since being ousted from power last year.

"Imran Khan's judicial remand in the Cipher case has been extended for 14 days," Khan's lawyer Salman Safdar told the media after the hearing.

On Tuesday, another court suspended Khan's three-year prison term for graft handed down early in August -- a judgment that kept him from contesting upcoming elections.

But authorities kept him in custody at Attock prison, around 60 kilometres (37 miles) west of Islamabad, after arresting him over a case alleging he had leaked classified state documents.

"This constitutes a manipulation of justice," Muhammad Shoaib Shaheen, another of Khan's lawyers, said Tuesday.

Barrister Salman Safdar (centre) speaks with members of the media in Attock on Wednesday. AFP

Wednesday's hearing was held under the colonial-era Official Secrets Act, with only lawyers present.

The case relates to a cable that Khan had touted as proof that he was ousted as part of a US conspiracy backed by the establishment, according to a report by the government's Federal Investigation Agency.

The United States and the Pakistan military have denied the claim.

The vice chairman of Khan's Pakistan Tehreek-e-Insaf (PTI) party, Shah Mahmood Qureshi, a former foreign minister, has also been arrested over the same case.

Agence France-Prsse