Two police officers and a policeman were killed Saturday in separate gunfire attacks in Iraq \'s capital of Baghdad and the eastern province of Diyala, the police said. Saad Muhsin Alwan, an Interior Ministry Lieutenant Colonel, was gunned down in a drive-by shooting by armed men using silenced weapons while driving on a high way in Baghdad\'s northwestern district of Shula, an Interior Ministry source told Xinhua on condition of anonymity. In western Baghdad, Abdul Razzaq Khalaf, a Brigadier General from the Iraqi intelligence service, was killed when gunmen using weapons fitted with silencers attacked his car in Jamia district, the source said. In Iraq\'s eastern province of Diyala, gunmen shot dead a policeman near his house in al-Abbara area, northeast the provincial capital of city of Baquba, some 65 km northeast of Baghdad, a source from the provincial operations command anonymously told Xinhua. Also in Diyala, Iraqi security forces carried out operations across the province during the past 24 hours and arrested seven suspects, including five wanted individuals, the source said. The attacks are part of the wave of assassinations by militia and gangs against Iraqi security members, officials and civilians. The attackers\' tactics varied from suicide bombings, gunfire by silenced weapons and sticky bombs attached to vehicles.