BEIJING (Reuters) - A Chinese farmer who had lost a leg in a train accident killed himself and three others in a bomb attack on the Ministry of Railways in Beijing last month, sources said on Wednesday. Two of those killed in the January 12 blast were ministry officials said the sources, who asked not to be identified. Five other people were injured in the attack. It was the first known bomb attack on a ministry in China since the communists came to power in 1949. Beijing newspapers reported the suicide attack the following day but gave scant details. They did not mention the ministry or say why Tian killed himself. But the sources said Tian Liucheng, a peasant in his 40s from the central province of Henan, blew himself up in a hut inside the ministry compound in western Beijing. "The roof was blasted away," one said. Tian had been demanding compensation from the ministry for years after he fell under the wheels of a locomotive and lost a leg, the sources said. He had jumped from a moving train in an attempt to escape railway police seeking to arrest him for failing to buy a ticket. The ministry gave Tian several thousand yuan (several hundred dollars) in compensation and offered recently to put him up at a retirement home, but he rejected the offer, the sources said. Police declined to comment. Separately, sources said hotels, airports and train stations in Beijing and the restive western Moslem region of Xinjiang were on alert against possible attacks by Moslem separatists.