A series of bomb attacks in seven provinces in central and northern Iraq on Monday left a total of 63 people killed and more than 260 wounded in a new escalation of violence in the country several months ahead of the proposed departure of U.S. troops.

The deadliest attack occurred in the city of Kut, some 170 km southeast of capital Baghdad, when a roadside bomb detonated at a marketplace in central the city at about 8:00 a.m. (0500 GMT) and was followed by a car bomb explosion, killing up to 34 people and wounding 64 others, a source from the provincial operations command told Xinhua.

Another deadly attack hit the Iraqi city of Tikrit, the capital of Salahudin province in north of Baghdad, when two suicide bombers entered the provincial counter-terrorism headquarters after they passed the checkpoints with their military uniforms and fake IDs in an attempt to free al-Qaida militants detained in the headquarters' jail.

But the security forces in the compound identified the suicide bombers and traded fire with them, killing one while the other blew up his explosive vest, the source from Salahudin's operations command told Xinhua.

The suicide attack resulted in the killing of three people, including the deputy chief of the headquarters, and the wounding of ten others, the source said.

Authorities of Salahudin province imposed curfew on the city for fear of further attacks, the source added.

Salahudin province, located in northern central Iraq, is a mainly Sunni province. Its capital city of Tikrit, some 170 km north of Baghdad, is the hometown of former President Saddam Hussein.

In Iraq's holy Shi'ite city of Najaf, six people were killed and 58 others wounded when two car bombs successively struck a police station, tasked with protecting the highways, in al-Hussein district in central Najaf, some 160 km south of Baghdad.

Elsewhere, three people were killed and up to 41 wounded in a car bomb explosion near al-Hindiyah police headquarters in eastern the city of Karbala, some 110 km southwest of Baghdad. The blast caused damages to the police building and destroyed several nearby police vehicles and civilian cars.

In Iraq's eastern province of Diyala, up to eight people were killed and 21 wounded in a car bomb explosion in the town of Bani Sa'ad near the provincial capital city of Baquba, some 65 km northeast of Baghdad, a provincial police source said.

In a separate incident, gunmen with their assault rifles attacked an Iraqi army checkpoint in northeastern Baquba and killed four soldiers before they fled the scene, the source said.

Meanwhile, a car bomb parked near the passport office in northeastern Baquba, ripped through a crowd of people who gathered outside the office, wounding 12 of them, the source added.

Also in Diyala, a policeman was killed and 10 people were wounded, including five policemen, in separate incidents across the province, the police reported.

Near Baghdad, a car bomb detonated near an Iraqi army patrol in Taji area, some 20 km north of Baghdad, killed a civilian and wounded nine people, including five soldiers, an Interior Ministry source told Xinhua on condition of anonymity.

In Baghdad, a total of two people were killed and 20 others wounded in four bomb attacks including a car bomb explosion targeted a convoy of a senior Iraqi official who escaped the blast unharmed, the Interior Ministry source said.

In northern Iraq, a motorcycle packed with explosives ripped through a parking lot in the Doumiz district in southern the city of Kirkuk, killing a civilian and wounding eight others, a local police source told Xinhua.

Meanwhile, a booby-trapped car detonated near a police patrol in al-Tiseen district in central Kirkuk, some 250 km north of Baghdad, wounding four policemen and three bystanders, the source said.

The latest attacks raise questions about the capabilities of the Iraqi security forces to maintain security in the country ahead of the Dec. 31 deadline of U.S. troops' withdrawal from the country.

Last week, the Iraqi political leaders agreed to give green light to Prime Minister Nuri al-Maliki to start talks with the United States about staying some of its troops in Iraq beyond the end of 2011 deadline only for training the Iraqi security forces on new weapons that Iraq proposed to purchase mainly from the United States to arm its fragile forces.

U.S. military forces are to pull out completely from Iraq by the end of 2011, according to security pact, named Status of Forces Agreement (SOFA), signed late in 2008 between Baghdad and Washington.

Maliki frequently said that SOFA cannot be renewed as stated in the agreement, but talks with the Americans is expected to let small force of U.S. troops to stay in Iraq beyond the end of 2011 deadline only for training Iraqi forces under the Strategic Framework Agreement, which was signed earlier with the SOFA between the two countries.