Karachi, April 26 : At least four people, including three Chinese citizens, were killed and several others injured in a explosion inside the University of Karachi campus on Tuesday in what police termed a terror attack, media reports said. The incident occurred near Confucius Institute - a China-funded teaching centre, Geo News reported, citing rescue sources. According to the reports, the blast took place in a van near the Confucius Institute. The dead Chinese comprised two women and one man, all employees of the institute. The fourth fatality was a male driver. Rescue and security agencies reached the site location and cordoned it off. Police sources said that there were seven to eight people in the van. The injured have been shifted to a nearby hospital, where the condition of three of the injured, which comprises another Chinese national is said to be critical, Geo News said. While Deputy Inspector General of Police, East, Muqaddas Haider said it was too early to say and Superintendent of Police, Gulshan, said that an investigation is being conducted, Karachi Police chief Ghulam Nabi Memon said that according to the initial investigation, it was a terror attack and a burqa-clad woman may be involved in the suicide blast. /IANS