By Asif Shahzad

ISLAMABAD (Reuters) -A Pakistani official accused former Prime Minister Imran Khan on Wednesday of sheltering aides and supporters wanted over attacks on the army following his arrest last week, and warned he had 24-hours to hand them over.

Khan and his representatives did not immediately respond to requests for comment.

"We have intelligence that some 30 to 40 terrorists who were involved in attacking our army's buildings and installations are hiding at Zaman Park," said Punjab province information minister Amir Mir, referring to the upscale Lahore neighbourhood where Khan lives.

"We're giving an ultimatum that these terrorists should be turned over to the police, or else there will be action," he told a press conference in the city.

He said Khan had 24 hours to surrender the suspects, and that a police operation would be launched if he did not comply.

Khan was arrested on May 9 on graft allegations, which he denies. He was released on bail last Friday, and on Wednesday the Islamabad High Court granted a bail extension until May 31, his lawyer Faisal Chaudhry said.

The arrest of the former prime minister, who was ousted in a parliamentary confidence vote in April last year, has deepened political instability in the South Asian nation of 220 million.

Pakistan was already facing its worst ever economic crisis, with a long delay in securing an IMF funding which is critical to avert a balance of payment crisis.

Thousands of Khan supporters had attacked and set on fire scores of government and public buildings, including the army's headquarters, following his arrest.

Punjab police had made a previous attempt to arrest Khan in March from his Zaman Park home, which ignited clashes that spread to many parts of Lahore in which one person was killed.

At Wednesday's press conference, Mir, the provincial information minister, said those wanted over the violence and more than 3,000 suspects already in custody would be tried by military courts.

The Human Rights Commission of Pakistan (HRCP), an independent civil rights group, had said on Tuesday it opposed the use of military laws to try civilians, saying it risked denying their right to due process.

Khan has previously disowned those involved in arson and attacks against the army, demanding an impartial inquiry.

The military has said the May 9 attacks against the army were "pre-planned" and ordered by Khan party's leaders, which he and his party deny.

(Reporting by Asif Shahzad; Editing by Alex Richardson)