Twenty-four people were killed and 53 others wounded in separate violent attacks in central Iraq on Saturday, police said. In Iraq's northern central province of Salahudin, a roadside bomb went off at a thoroughfare in the provincial capital city of Tikrit, and minutes later a car bomb explosion struck a police force which arrived at the site of the first blast, a provincial police source said. The two blasts killed a total of five people and wounded 22 others, the source said, adding that three policemen were among the killed and several others were among the wounded. The attackers apparently followed the old tactic which depends on creating an initial explosion to attract security forces and people, then they set off another blast to get heavier casualties, he said. Also in Tikrit, a police officer and his son were killed when a sticky bomb attached to their car detonated in the northern part of the city, which located some 170 km north of the Iraqi capital of Baghdad, the source added. In Baghdad, Mohammed Bdiewi, a journalist heading Free Iraq Radio station, was shot dead in Baghdad's central district of Karrada after he had a dispute with an officer and soldiers guarding a presidential site belonging to Iraq's Kurdish President Jalal Talabani, a police source said. Bdiewi, also a teacher of the media college at Baghdad's Mustansriyah University, was heading to his office when the incident occurred, the source said. Iraqi Prime Minister Nuri al-Maliki ordered to arrest the officer who believed to shoot Bdiewi dead, local media reported. In a statement, the Iraqi Journalists' Syndicate condemned the incident and said "this disgraceful act which was perpetrated against an Iraqi journalist by the checkpoint indicates lack of respect toward journalists as well as for all citizens." Earlier, Muaiyad al-Lami, head of the Iraqi Journalists Syndicate, said that more than 390 journalists have been killed in Iraq since 2003, and up to 17 were killed in 2013, the highest toll since 2008. In a separate incident, an army force clashed with militants believed to be linked to al-Qaida organization in Abu Ghraib area, some 25 km west of Baghdad, and killed seven of them at their safe house in the area, a local police source said. In Baghdad's southern suburb of Hour Rijab, a roadside bomb went off near a checkpoint manned jointly by Iraqi soldiers and members of a government-backed Sahwa paramilitary group, killing a Sahwa member and wounding four soldiers, the source said. Separately, a police officer and five civilians were wounded in two roadside bomb attacks in eastern and northern parts of the capital, the source added. In Iraq's eastern province of Diyala, a suicide bomber drove his explosive-laden car into a checkpoint near Udhiem area, some 70 km north of the provincial capital city of Baquba, which is about 65 km northeast of Baghdad, a provincial police source said. The huge blast killed a soldier and two policemen and wounded 17 people, including four policemen, the source said, adding that two military vehicles and four civilian cars were left charred at the scene. In a separate incident, Iraqi security forces carried out an operation at Himreen mountain in the northeastern part of Diyala, and killed three gunmen said to be linked to al-Qaida militants, the source said. Meanwhile, a helicopter gunship pounded a truck carrying heavy machinegun in Enjanah area near the town of Qara Tabba, some 175 km northeast of Baghdad, destroying the truck and killing two gunmen aboard, the source said, adding that four people were wounded in the same area when gunmen opened fire on a civilian car.