Islamabad police gear for Imran Khan's supporters at his court hearing.

Police in the federal capital has imposed an emergency order banning gatherings as supporters of Pakistan Tehreek: e: Insaf (PTI) Chairman Imran Khan are expected to march to the capital on Friday where the former prime minister will appear for a court hearing.

His arrest earlier this week, which sparked deadly unrest in the nuclear: armed nation, was ruled "invalid and unlawful" by the Supreme Court on Thursday. The apex court also directed the former premier to appear before the IHC on Friday (today).

Khan's Pakistan Tehreek: e: Insaaf (PTI) party said thousands of "peaceful Pakistanis" from across the country will gather in Islamabad in solidarity with their leader.

Khan, 70, an international cricket hero: turned: politician, will appear before the Islamabad High Court at 11 a.m. (0600 GMT) for a hearing on his petition challenging the anti: corruption action against him, on orders of the top court.

His arrest aggravated instability in the country of 220 million people at a time of severe economic crisis : with record high inflation, anaemic growth and a delayed IMF funding.

Nearly 2,000 people have been arrested so far and at least...