Baghdad, Iraq (CNN) -- A wave of bombings targeting Shiites, a market in Baghdad and a neighborhood in Anbar province killed at least 61 people and wounded more than 100 others Friday, police said.
The strikes conjured memories of the bloodshed that once engulfed both the capital city and the vast province every day.
No one has claimed responsibility for the string of attacks, but authorities believe that such coordinated bombings bear the hallmarks of al Qaeda in Iraq.
The bombings come days after Iraqi and U.S. officials announced that they had killed the two most wanted al Qaeda leaders in the country. Although the deaths hurt the insurgents, military officials don't discount insurgents' continued ability to carry out attacks.
This week, Maj. Gen. Qassim Atta, spokesman for the Baghdad Military Operations Command, boasted about the killings of insurgent leaders Abu Ayyub al-Masri and Abu Omar al-Baghdadi.
He said security forces must capitalize on this "great victory" but cautioned about the possibility of reprisals.
Of the Iraqi-U.S. joint operation Sunday that killed the two leaders, Atta said, "We had information that they were planning attacks that would target churches, Shiite mosques and bridges, and the security forces took precautions and prepared security plans specifically for this."
Former Deputy Minister of Health and Sadrist politician Hakim al-Zamili said he thinks Friday's bombings could be retaliation for the killing of the al Qaeda in Iraq leaders.
"This political and government vacuum led to such bombings and will lead to many disasters for the Iraqi people," he said.
The strikes occur during the delay in the formation of a government, and many observers fear that a political vacuum could portend an increase in violence, such as the sectarian bloodshed that took place in early 2006 while the government was being formed.
Among the string of attacks:
• Two car bombs targeted worshipers in Sadr City in eastern Baghdad, killing 39 and wounding 56 people. Also, a car bomb exploded outside one of Shiite cleric Muqtada al-Sadr's offices there, wounding five people.
The attacks enraged Sadr City residents, who say the government is turning a blind eye to militants. Al-Sadr's office distributed a statement Friday afternoon calling for his followers to show restraint and called for three days of mourning. Al-Sadr has a political movement and a large grass-roots following.
• In southeastern Baghdad, eight people died and 23 were wounded when a car bomb and a roadside bomb detonated outside Muhsin al-Hakim mosque.
• In the northwestern Baghdad neighborhood of Hurriya, a car bomb explosion outside Hadi al-Chalabi mosque killed five people and wounded 10.
• A roadside bomb outside the Sadreen mosque in the Zafaraniya neighborhood in southeastern Baghdad killed two people and wounded seven.
• One person was killed and six people were wounded when a roadside bomb exploded in an outdoor market in the southern Baghdad district of Dora.
• A car bomb exploded outside a Shiite mosque in the Ameen neighborhood in southeastern Baghdad, wounding two people.
• West of Baghdad, in the Anbar province town of Khaldiya, six people were killed and 10 were wounded when six roadside bombs exploded in a residential area where a police officer and a judge lived. Authorities imposed a curfew.
CNN's Mohammed Tawfeeq and Jomana Karadsheh contributed to this report.