The wave of bombings carried out across Baghdad on Dec. 22, 2011 has renewed domestic and international concern about Iraq, just days after the last U.S. combat troops withdrew from the country and U.S. President Barack Obama marked the end of the war after nearly nine years.

Sixteen bombs went off in various Baghdad locations, killing at least 69 people and injuring at least 200.

Who is behind the bombings?

No one has claimed responsibility but analysts and U.S. officials say the bombings bear the hallmarks of al-Qaeda in Iraq. The analysts point to there being no particular target, the victims were overwhelmingly civilian, that it was a series of bombings, and the timing.

Moharram, the first month of the Islamic calendar, was observed in December when the bombers struck. It's the month when Shia Muslims mourn the death of the prophet Muhammad's grandson, Imam Hussein, the event that led to the Sunni-Shia divide. Al-Qaeda in Iraq, a Sunni group, often targets Shias.

They say the motive, if it was an al-Qaeda attack, was to inflame the Sunni-Shia conflict and show the terrorist group is still capable of major attacks.

There has been a high level of violence in Iraq since the overthrow of Saddam Hussein. While the recent bombings had tragic consequences, are they all that extraordinary?

The violence and bombings in Iraq have continued nearly every day but not on the scale that took place between 2005 and 2007.

However, these latest bombings are reminiscent of a series of bombings and attacks across Iraq on Aug. 15 that left about 70 dead. Iskander Witwit, a member of the Iraqi parliament's security and defence committee, told the Washington Post that the bombings were "expected" and the Post's own editors had warned two weeks ago that, "Many Iraqis worry that, after the last U.S. troops depart this month, the sectarian bloodletting that ravaged the country [until] 2007 will resume."

What's the significance of the timing?

The U.S. troop withdrawal on the weekend seems key, and a series of bombings like the most recent one would be weeks in the planning, so analysts have been downplaying a connection to the breakdown in relations behind the Iraqi government's Shia, Sunni and Kurdish factions.

si-220-nouri-al-maliki-0182

Iraq's Prime Minister Nouri al-Maliki has ordered the arrest of Iraq's Sunni vice-president, accusing him of running a hit squad, as a conflict with Sunni members of his coalition government continues. (Hadi Mizban/Associated Press)

Nevertheless, Iraqi Prime Minister Nouri al-Maliki said in a statement, "The timing of these crimes and the places where they were carried out confirm ... the political nature of the targets."

What going on with Iraqi politics right now?

Al-Maliki has accused Vice-President Tariq al-Hashemi of running a hit squad that killed government officials and ordered his arrest. Al-Hashemi is one of the Sunni leaders in Iraq's governing coalition. He denies the charges and has taken refuge in Iraq's autonomous Kurdish region.

Al-Maliki is demanding the Kurds return al-Hashemi to Baghdad.

Last week on CNN, another top Sunni official, Deputy Prime Minister Saleh al-Mutlak, called al-Maliki the "biggest dictator ever." Al-Maliki responded by trying to get parliament to dismiss al-Mutlak but that effort is currently on hold.

Al-Maliki, from Iraq's Shia majority, heads a coalition government that includes Sunni and Kurdish representation but it appears close to collapse. The predominantly Sunni political bloc, Iraqiya, is boycotting both parliament and the cabinet. Al-Hashemi and al-Mutlak represent Iraqiya.

Al-Maliki's critics accuse him of concentrating power in his own hands and excluding the Sunni minority, despite a power-sharing arrangement.

si-220-iraq-bombing-0182655

People gather at the scene of a car bomb attack in Baghdad Dec. 22. A wave of bombings ripped across the city, killing and wounding hundreds of people, officials said, in the worst violence Iraq has seen for months. (Karim Kadim/Associated Press)

Differences over Syria may also be aggravating the conflict in Iraqi governing circles. Iraqiya strongly supports the Syrian opposition while al-Maliki "has set himself apart from the rest of the Arab League by refusing to break with the Syrian government of Bashar al-Assad," according to the Washington Post.

The irony of al-Maliki standing by an embattled Baathist ruler like al-Assad — Saddam Hussein was also a Baathist — owes much to Iran's influence in Iraq.

What's Iran's role?

The Iranian regime supports and influences al-Maliki's government next door in Iraq. "This has been evident since the government was elected but has got more noticeable in recent months," according to Paul Rogers, a leading international affairs expert at the University of Bradford in the U.K.

Of course all this is happening while the U.S. and its allies are trying to constrain Tehran over their concerns about Iran's nuclear program. Rogers argues the U.S. withdrawal from Iraq "undoubtedly gives the leadership in Tehran a substantially increased sense of regional influence."