A series of car bombings and shootings, mainly targeting Shiite areas across Iraq, on Monday killed at least 61 people, including Iranian pilgrims, and wounded some 200, apparently in an attempt to stir up sectarian strife. The worst violence on Monday occurred in Baghdad, when eight car bombs and a roadside bomb ripped through bus stops, marketplaces and other crowded areas in the mainly Shiite neighborhoods across the capital city, killing a total of 12 people and wounding some 109. In Iraq\'s oil-rich city of Basra, some 550 km south of Baghdad, 11 people were killed and 35 wounded when two car bombs went off almost simultaneously in the western part of the city. Elsewhere, a roadside bomb went off near fighters of government- backed paramilitary group, also known as Awakening Council group, in the city of Samarra, some 110 km north of Baghdad, killing two fighters and wounding 18, a local police source told Xinhua on condition of anonymity. The fighters of the Sunni group were gathering near an Iraqi army base to collect their salaries when the bomb went off, the source said. In a separate incident, unidentified gunmen opened fire on another group of Sunni fighters as they were also collecting their salaries in the town of Yathrib, some 85 km north of Baghdad, killing one of them and wounding two others, the source added. Meanwhile, a suicide bomber blew up his explosive-laden car at the checkpoint manned by members of another Sunni paramilitary group in the city of Baiji, some 220 km north of Baghdad, killing two fighters and wounding five others, a local police source told Xinhua. Also in the day, a car bomb parked on a main road near the city of Balad, some 80 km north of Baghdad, went off near a bus carrying Iranian pilgrims, killing eight pilgrims and wounding 19 others, including five women, a local police source anonymously told Xinhua. The Iraqi driver of the bus and a passerby were also wounded by the blast, the source said. The Iranian pilgrims were on their way back to Baghdad after finished their visit to the Shiite shrines in Samarra, 110 km north of Baghdad, the source added. In Iraq\'s eastern province of Diyala, three people were killed and three wounded in two bomb attacks near the provincial capital city of Baquba, some 65 km northeast of Baghdad, a provincial police source anonymously told Xinhua. In western Iraq, 12 kidnapped policemen were killed and four wounded during an overnight raid by the Iraqi forces on an insurgents\' safe house in a desert area between Baghdad and Jordan in Anbar province to free kidnapped policemen, a provincial police source told Xinhua on Monday morning. It was not clear whether the victims were executed by their abductors or were caught in the crossfire, the source said. The volatile province was the scene of another deadly attack against the police late on Sunday, when unidentified gunmen attacked a police station in the town of Rawa, 260 km northwest of Baghdad and killed ten policemen before they fled the scene, according to the provincial police. Anbar province is the heartland of the Iraqi Sunni Muslims. Its capital Ramadi has been one of the main areas of the Sunni protests against the Shiite-led government in Baghdad since last December. No group has so far claimed responsibility for the deadly attacks, but the al-Qaida front in Iraq, in most cases, were responsible for such massive attacks in the country, raising fears that the terrorist group and other militia could return to widespread violence. Monday\'s bombings came amid escalation of sectarian tensions between the Sunni and Shiite communities, which have been at its highest level since the U.S. troops pulled out of the country at the end of 2011. For five months, the Sunni Muslims have been carrying protests against the Shiite-led government in the Sunni provinces and the Sunni districts in Baghdad. The Sunnis accuse the government of marginalizing them, and claimed that the Shiite-dominated Iraqi security forces were indiscriminately arresting their sons and torturing them. The deadly bomb attacks in Iraq pushed the Iraqi Prime Minister Nuri al-Maliki to vow that he will overhaul security plans and will carry out changes in his security personnel. \"Now we are about to make changes in the high and middle positions, as well as in the (security) plans,\" Maliki told reporters in a news conference after the attacks.