BURAIDAH — Four construction workers were killed when a building they were working on collapsed on a university campus in Buraidah about 360 kilometers northwest of Riyadh, civil defense authorities said. Another six workers were injured in the collapse, which took place Monday on the campus of Al-Qassim University, the Civil Defense said, adding that some 50 workers were at the site at the time. Al-Qassim Emir Prince Faisal Bin Mishal inspected the site and closely followed the rescue operation. He has also constituted a high-level committee to probe into the accident. Muhammad Al-Dubasi, spokesman of Health Department in Al-Qassim, said that six injured workers were transferred to Buraida's Central Hospital, and Sulaiman Al-Habeeb Hospital and Al-Bukairiyah Central Hospital. The accident occurred when the concrete mixture was pouring mortar on the steel support rods of the building, located in the northwestern side of the university's main building. Bandar Al-Roshodi, the university spokesman, told Saudi television news channel Al-Ekhbariya that the workers were mostly from Pakistan. “Until now we are searching,” he later a new agency.The trapped workers were of “different nationalities,” Roshodi said. Asked about the chances of more survivors, he said: “We have hope, God willing.”