By Wangui Kanina NAIROBI, June 12 (Reuters) - Kenyan police said on Tuesday they had arrested three people over an explosion in Nairobi that killed one person, injured scores more and revived traumatic memories of past bomb attacks blamed on al Qaeda. Despite interrogating the three suspects -- whose names and nationalities were not released -- police still could not clarify what caused Monday's rush-hour blast. Witnesses and some policemen at the scene spoke of a possible suicide bomb, with one or two people carrying a suspicious-looking bag near a bus-queue and restaurant. "Following the explosion, police are holding three suspects for interrogation," police spokesman Eric Kiraithe said. The explosion left a mangled corpse lying in the street with a severed foot lodged in a shop window, sent some passers-by flying through the air and shattered windows. "It is known that he is a male African in his mid-thirties," Kiraithe said of the dead man. Considered relatively peaceful compared to some of its neighbours in volatile east Africa, Kenya was hit by large bombs in 1998 and 2002, blamed on Osama bin Laden's al Qaeda network. The first, at the U.S. Embassy in Nairobi, killed more than 200 people, the other 15 at an Israeli-owned hotel in Mombasa. Suspicion among Kenyans for Monday's blast has fallen on both militant Islamists from neighbouring Somalia and members of the local criminal Mungiki gang engaged in an increasingly bloody street war with the police. Others say the attacker could have been a loner with a grudge. "INVISIBLE THREAT" Local media reported that two men carrying a bag had tried to board a bus near the Ambassadeur hotel minutes before the blast, but had then walked towards a packed restaurant after discovering the vehicle was full. It was going to the airport. Some torn papers with English and Arabic script from the Koran were found and taken away by anti-terrorism officers. Police said the blast, which hurt 37 people, was not big. "This is a very small explosion which could not burst a bus tyre less than two metres away," Kiraithe said. Despite that, Kenyans reacted to the explosion with fear it could be a foretaste of more, especially in an election year. "Our vulnerability as individuals and a nation came to the fore yesterday morning when an explosion tore through the tranquillity of our city streets," the daily Standard said. "This rekindled memories of years past, when terrorists visited terror on Nairobi and Kikambala (near Mombasa), killing hundreds of innocent people ... We must accept the biting truth: the invisible threat is here with us." There were also concerns the explosion could damage Kenya's image abroad. Nairobi is home to thousands of expatriates and Kenya is one of Africa's top tourist destinations. "I came to my job early this morning without fear ... But foreigners may fear coming to Kenya because of this," said Fred Mumo, selling lottery tickets near the blast site on Tuesday. (Additional reporting by Victor Adar)
