At least four people have been killed and dozens more injured in a series of explosions in Addis Ababa, international news sources report. Six bombs went off in the morning of 12 May, mostly in the crowded Mercato and Piazza areas in the city centre. These were followed in the afternoon by a further two or three explosions in the southwest of the city. So far no-one has claimed responsibility for the blasts, which are the latest in a series of attacks to have affected the Ethiopian city since the start of the year. In the past the government has accused neighbouring Eritrea of being behind the bombings. It has also pointed the finger of blame at the political opposition, which is contesting the results of the May 2005 legislative elections which returned the government to power amid claims of massive fraud.