Three children were killed and four wounded when a bomb went off at a football pitch in the Iraqi city of Baquba, local authorities told Deutsche Presse-Agentur dpa on Monday, while a series of arrests and minor attacks were reported elsewhere. The children were killed when a bomb went off on Sunday evening as they were playing football near a public playground in the city's industrial complex district. Baquba, 57 kilometres north-east of Baghdad, is the capital of the province of Diyala, which has seen a surge in violence despite a joint US-Iraqi military offensive to flush out insurgents linked to the al-Qaeda terrorist network. Also in Baquba on Sunday, three US soldiers were killed in a suicide bombing, a US military statement said. And in another incident, three Iraqi policemen were killed and three others wounded when gunmen attacked a police centre in the Zaghaniya area of north-western Baquba.