Fourteen people had been injured with three of them in critical condition as of Monday midnight, a few hours after an explosion hit downtown Nairobi, medics told Xinhua. Simeon Monda, Deputy Director of the Clinic Services in the Kenyatta National Hospital in Nairobi said they had admitted a total of 14 injured after the explosion. \"Three of them are seriously injured,\" he said. \"One of them is undergoing an operation.\" Monda said the 11 slightly injured are all stable and are expected to be discharged from the hospital Monday or Tuesday. The explosion, which so far has killed one, is the second of its kind in Nairobi on Monday. It occurred around 7:56 p.m. local time. Local police officer Binti Hamadi said earlier that an unidentified man hurled a hand grenade on commuters who were waiting to board their public passenger vehicles to go home along Racecourse road, a formerly OTC bus stop in downtown Nairobi. The latest attack came hours after a hand grenade attack injured at least 14 Kenyans in a bar in Nairobi. Police officer said earlier that they are investigating whether the two attacks are linked. The attacks came two days after the U.S. embassy in Kenya warned that an attack was imminent as the nation is fighting Islamist militants in neighbouring Somalia.