An explosion followed by gunfire was reported on a major road in Pakistan's commercial capital of Karachi on Saturday, according to Reuters and local media reports.Pakistani broadcasters ARY News and Geo News reported that the blast occurred near the offices of the Pakistan Rangers, a paramilitary force, on a road close to several universities and the Pakistan Meteorological Department.According to Al Jazeera, the explosion took place near a gate leading to the Rangers' offices, after which gunfire was heard in the area. Sources quoted by the broadcaster said clashes were underway following the blast.Dawn reported that special security units, including the Rapid Response Force and police commandos, were rushed to the scene, while police and paramilitary personnel sealed off the area.