The arrest, ruled "invalid and unlawful" by the Supreme Court a day earlier, fuelled instability in the nation of 220 million at a time of economic crisis, with record inflation, anaemic growth and delayed IMF funding.

"They had no justification to arrest me," Khan told British news outlet The Independent at the Islamabad High Court.

"I was abducted. It seems as if there was a law of jungle."

Almost 2000 people have been arrested for violence since Tuesday, when Khan was detained by the anti-graft agency in a land fraud case.

At least eight have been killed as his supporters clashed with police, attacked military establishments and set other state buildings and assets ablaze, prompting the government to call in the army to help restore order.

"The Islamabad High Court has given a two-week bail and also ordered the (anti-graft body) not to arrest Imran Khan during this period," his lawyer Faisal Chaudhry told reporters after the hearing.

Khan arrived amid tight security at the court in Islamabad on Friday as his supporters clashed with police elsewhere in the capital, broadcaster Geo TV reported.

Khan, wearing dark glasses and dressed in a sky blue shalwar kameez - the loose shirt and trousers popular in Pakistan - and a dark waistcoat, walked into the court surrounded by lawyers and security forces, TV footage showed.

He was seen in footage waving at cameras and making a victory sign with his fingers as he walked into the court.

Khan's Pakistan Tehreek-e-Insaaf (PTI) party said thousands of "peaceful Pakistanis" would gather in Islamabad in solidarity with their leader after the Supreme Court ruled Khan's arrest invalid on Thursday.

"The manner of execution of the arrest warrant ... against petitioner is invalid and unlawful," the Supreme Court order said.

"The execution of the said warrant violated the petitioner's right of access to justice and the sanctity and safety of the court."

Khan was arrested a day after the powerful military rebuked him for repeatedly accusing a senior officer of trying to engineer his assassination and the former armed forces chief of being behind his removal from power last year.

Protesters have attacked military establishments, ransacked the house of a top army general in the eastern city of Lahore, and set ablaze state buildings and assets in other places.

The army warned Khan's supporters it would respond firmly if there were further attacks on its assets, saying in a statement on Wednesday the violence at its installations was "pre-planned" and ordered by his party leadership.

Khan's party has maintained it has only called for peaceful protests.

Australian Associated Press