Iraqis stand in front of the collapsed building after a seris of deadly bombings on Friday in Baghdad. Reportedly at least 60 people were killed and 117 wounded in the bombings in Baghdad and western Anbar province. [Xinhua/AFP Photo]

Iraqis on Friday witnessed the most bloody day in the past three weeks, with at least 60 people killed and 117 others wounded in a string of car and roadside bombings in Baghdad and western Anbar province.

The most serious attack occurred close to Shiite cleric Muqtada al-Sadr's office in Sadr city, killing 39 and wounding 56, said the source on condition of anonymity, adding that actually there were two cars loaded with explosives and were detonated together.

In eastern Baghdad, another car bomb and a roadside bomb explosion attacked a Shiite mosque, leaving 8 killed and 23 injured, he said.

Earlier in the day, a booby-trapped car apparently targeting a Shiite mosque blasted in northern Baghdad, killing 5 and wounding 14 others.

A moment later, a market in Haifa street close to the Justice Ministry was also attacked by a car bomb explosion, wounding seven. Xinhua reporters could clearly see the heavy smoke rising from the blast site. Ambulances rushed to the site just a few minutes after the explosion.

In a separate blast in southern Baghdad, six people were injured, said the source.

Iraqi officials have blamed the attacks as al-Qaida's revenge after the group's top leaders were killed by security forces last week.

"This is a revenge by al-Qaida for what they lost; we expect such terrorist acts to continue," Baghdad security spokesman Qassim al-Moussawi told media.

Iraqi Prime Minister Nuri al-Maliki and the U.S. military announced last Monday the killing of two top al-Qaida leaders in a nighttime rocket attack on a safe house near the city of Tikrit, the capital of Salahudin province.

The two top al-Qaida leaders were Abu Omer al-Baghdadi and Abu Ayyub al-Musri, who are the most wanted by U.S. and Iraqi forces.

One day after the announcement, the security forces also said they killed Ahmed al-Obaidi, also known as Abu Suhaib, the military leader for al-Qaida terrorist organization in the provinces of Nineveh, Kirkuk and Salahudin.

Local analysts believe the killing announcement of al-Qaida top leaders can be seen as victory for the country's security forces, who were blamed for failing to protect civilians against terrorists. However, they also warned of very possible revenge attacks soon.

Also on Friday, several separate roadside bomb explosions rocked Iraq's western province of Anbar, killing eight people and wounding 11 others.

The attacks targeted a judge's house and a police officer's house as well as some civilian buildings in Kalidiya, a town locates 83 km west of Baghdad, the interior ministry source told Xinhua.

According to the source, five blasts happened almost together at first, leaving seven dead and nine injured. When local security forces arrived, another bomb was detonated, killing one soldier and wounding two.

Anbar has long been a stronghold of insurgents like al-Qaida group after the U.S. invasion of Iraq in 2003. Even local Sunni militia has turned to cooperate with Iraqi government and U.S. forces to fight against al-Qaida in the past years, deadly attacks occurred continually.

Meanwhile, Shiite commemorations in Iraq have often been targeted by various armed groups, especially al-Qaida. Analysts and local media believe the attacks against Shiites were meant to spark sectarian violence in the country.

The situation in Iraq now is very sensitive since political blocs are battling each other for cabinet formation after the country's parliamentary elections were held last month. Analysts said they expected more attacks in the near future as long as the cabinet forming process takes.