A series of gunfire and bomb attacks, including four successive blasts in Iraq's holy Shi'ite city of Karbala, killed a total of 17 people and wounding dozens in a new escalation of violence in the country few months ahead of the departure of U.S. troops.

The deadliest attack occurred when four bomb explosions in central the city of Karbala, some 110 km south of Baghdad, killed up to ten people and wounded some 90 others.

The first blast occurred at about 9:30 a.m. (0630 GMT) when a bomb attached to a car parking outside the passport and identity card office in central Karbala detonated and minutes later a second bomb blast followed at the scene.

About 20 minutes later, two blasts in a quick succession went off when Iraqi security forces spread at the scene of the earlier two blasts.

"Our latest reports said that 10 people were killed and 90 others wounded in the four bomb attacks of Karbala," said a source from Karbala's police, citing reports from the city's health office.

Many Iraqi soldiers and policemen were among the victims, the source said, adding that some of the wounded people left the hospitals after they received treatment.

Iraqi security forces sealed off the scene and blocked all the roads leading to the heavily populated area in central the city which also includes Karbala's provincial council and the provincial police headquarters, the source said.

The attackers apparently followed 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, the source added.

In west of Baghdad, meanwhile, gunmen planted two bombs in the house of a policeman and blew them up in the town of Khaldiyah, some 80 km west of the capital, killing the policeman and two of his family members.

The blasts destroyed the house and caused damages to nearby houses, wounding four people inside.

Separately, a government employee was gunned down by drive-by shooting when gunmen opened fire on him while driving in al- Hurriyah neighborhood in northwestern the capital, an Interior Ministry source told Xinhua on condition of anonymity.

In a separate incident, gunmen using silenced weapons broke into a money exchange office in Baghdad's northeastern district of Shaab, killing the owner of the office and stealing the money, the source said.

Also in the capital, a bodyguard of Mahmoud al-Mashhadani, ex- parliament speaker, was serious wounded when a sticky bomb attached to his car detonated in al-Qadsiyah neighborhood in western Baghdad, the source added.

In Iraq's northern city of Mosul, two policemen were killed and three wounded in a roadside bomb explosion near a police patrol in a village north of Mosul, some 400 km north of Baghdad, a local police source said.

Violence has been increased in the Iraqi cities as the Iraqi forces are preparing to take over control of security alone after the proposed departure of U.S. troops by the end of the year withdrawal deadline.

Iraqi officials frequently said that Iraqi security forces are capable of maintaining internal security, but they warned that they cannot yet to provide security on the country's borders.

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.

However, Iraq is reportedly negotiating with the United States to let U.S. military trainers to stay in Iraq beyond the deadline only for training Iraqi forces.