evidence: Unrest has continued to grip Pakistan after former prime minister Imran Khan pleaded not guilty to corruption following his arrest on Tuesday. [...] Mr Khan's arrest has dramatically escalated tensions between him and the military at a time of economic crisis. [...] Mr Khan's Pakistan Tehreek-e-Insaf (PTI) party called his arrest in the capital Islamabad an "abduction" and said it would challenge its legality in court.