Al Qaida in Iraq has claimed responsibility for a wave of bombings and suicide attacks that killed around 60 people on the 10th anniversary of the U.S.-led invasion that ousted Saddam Hussein.
A decade after U.S. and Western troops swept into Iraq to remove the Sunni strongman, Iraq still struggles to overcome violence, sectarian tensions and political instability that test the fragile unity among Shi'ites, Sunnis and ethnic Kurds.
Islamic State of Iraq, the country's al Qaida wing, is regaining strength, invigorated by the Sunni Muslim rebellion in next door Syria and has carried out dozens of high-profile attacks since the start of the year.
Car bombs, roadside explosions and suicide attacks on Tuesday hit mainly Shi'ite districts and security forces in Baghdad and other cities, including a bomber who detonated his blast inside a restaurant in the northern city of Mosul.
"What has reached you on Tuesday is just the first drop of rain, and a first phase, for by God's will, after this we will have our revenge," the al Qaida statement posted on a jihadist website late on Tuesday said.
Sunni Islamists see Iraq's Shi'ite-led government as oppressors of the country's Sunni minority and target Shi'ites to try to provoke a sectarian confrontation like the inter-communal slaughter that killed thousands in 2006-7.
While violence is below the level of the Shi'ite on Sunni bloodshed that killed tens of thousands a few years ago, suicide bombers have struck nearly two times a week since January, a rate Iraq has not seen for several years.
The Iraq war began shortly before dawn in Baghdad on Thursday, March 20, 2003, with U.S. air strikes on the capital. Shortly afterwards, President George W. Bush, told Americans late on March 19 U.S. time that the offensive was under way.
Iraq's sectarian and political rivalries are still raw, keeping the OPEC country vulnerable to the influence of its neighbours, especially Shi'ite Iran and Sunni power Turkey.
Its power-sharing government split among Shi'ite, Sunnis and Kurdish factions has been all but paralyzed by disputes for more than a year. Critics of Shi'ite Prime Minister Nuri al-Maliki say he is amassing power at their expense.
To the country's north, Iraq's autonomous Kurdistan region is increasingly bristling against central government control and seeking ways to develop its own oil resources and defy Baghdad by shipping crude to its northern neighbour Turkey.
To the west of Baghdad, thousands of Sunni Muslims have protested for months, blocking a key highway to Jordan and Syria in protest against the Shi'ite-led government that it says has marginalised them since the fall of Saddam.
Syria's growing conflict over the border is stirring up Iraq's volatile mix, exposing the country to the rivalry between Ankara, which backs Sunni rebels fighting President Bashar al-Assad, and Shi'ite power Tehran which sponsors him.
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