Two people were killed and five injured when a bomb exploded near two churches in the northern Iraqi town of Mosul on Wednesday, dpa quoted security sources as saying. The blast took place in the centre of the town, the Voices of Iraq news agency reported. Last year, thousands of Christians fled Mosul, 400 kilometres north of Baghdad, after violence killed 40 members of the religious minority. Roughly 750,000 Christians live in Mosul, most of them from the Chaldean sect, though there are pockets of adherents to the Eastern Orthodox, Assyrian, and Catholic churches. The number is believed to be on the decline. Earlier Wednesday, four policemen were shot and killed by unidentified gunmen at a checkpoint outside Baghdad, security officials said. The assailants fled the scene of the attack in Abu Ghraib, 20 kilometres from the capital. Police said they managed to capture a suicide bomber near Baghdad before he detonated his deadly device. Sporadic violent incidents continue to plague areas outside Baghdad ahead of national elections slated for March 2010. -- SPA