At least four people were killed Thursday in two separate attacks north of the Iraqi capital Baghdad, amid rising sectarian and political tensions in the country, dpa quoted police as saying. Three soldiers were killed and five injured when unknown gunmen attacked a security checkpoint in al-Dulaya, 170 kilometres north of Baghdad. One civilian was killed and seven wounded in a bomb blast in Baquba, 60 kilometres north-east of Baghdad, police said. No group has claimed responsibility for the attacks.