"Three policemen were killed and two others wounded by a bomb targeting their patrol in Al-Muqdadiyah this morning," a police lieutenant colonel in the town said.

Dr Ahmed Ibrahim, from the main hospital in the nearby provincial capital Baquba, 60 kilometres (35 miles) north of Baghdad, confirmed the toll.

While violence has decreased from its peak in 2006 and 2007, attacks remain common across Iraq. There were attacks on 27 of the 31 days in July.

Official figures put the number of people killed in attacks in July at 325, the highest monthly death toll since August 2010.