Police in capital fired warning shots and used tear gas to stop protests against the hike in public transport fares for the second day on Friday, injuring many citizens and detaining 40 protesters, report said. The protests started Thursday when students and residents blocked a key road in Islamabad's Bara Kahu neighborhood, unhappy with the 20 percent increase in bus fares, said local police officials. On Friday, rock-throwing protesters blocked a main road to Islamabad's airport, police official Mohammed Iqbal said. Iqbal said the violence prompted the government to rescind the fare increase late Thursday, but the protests continued Friday with students demanding the release of protesters arrested the day before. Protesters said more than a dozen students were in police custody.