It was a brazen, complex attack worthy of Iraq's al Qaeda at its peak. Two bombs minutes apart killed, maimed and distracted while a team of suicide attackers blasted into a Baghdad police base to try to free jailed insurgents.
Tuesday's high-profile assault on a anti-terrorism police unit in Baghdad was the latest in a drive by the Islamic State of Iraq, al Qaeda local affiliate, to make good on a pledge to win back ground lost in its war with American troops – its leader has even threatened to strike at the United States.
Insurgents ultimately failed to free their prisoners, but the intended message was clear: we're back.
With Sunni Muslim militants trickling into neighboring Syria to battle President Bashar al-Assad, security experts say al Qaeda is reaping funds, recruits and better morale on both sides of the border, reinvigorating it after years of losses against U.S. forces and their Iraqi allies.
Islamic State of Iraq and other Sunni militant groups hate Assad's minority Alawite sect, a distant offshoot of Shi'ite Islam, which they see as a heretical oppressor of Sunnis.
Hostile to Shi'ites in general, they also oppose the Shi'ite-led government of Iraqi Prime Minister Nuri al-Maliki. Iran, the major Shi'ite power in the region, is a firm ally of Assad and wields great influence in Baghdad.
Al Qaeda appears to be exploiting Sunni-Shi'ite tensions fuelled by the increasingly sectarian conflict in Syria. Many Sunnis in Iraq are already disgruntled with what they see as Maliki's determination to minimize their share in power.
"The Syrian crisis is a venue in which an Iraqi-dominated al Qaeda branch is better able to attract fighters and resources to its cause," said Ramzi Mardini, an analyst with the Institute for the Study of War in Washington. "This may be a revival of confidence on the part of Sunni extremists."
CHANGING SIDES
Once at the heart of a Sunni insurgency against U.S.-led forces, al Qaeda lost many commanders to Iraqi and U.S. troops. Sunni tribes turned the tide against it from 2007, when they fought the group with U.S.-supplied guns, partly in revulsion at the indiscriminate carnage it had inflicted on civilians.
Iraq's violence has eased since the sectarian bloodbath of 2006-2007, but each month since the last American troops left in December al Qaeda has claimed responsibility for at least one major, well-coordinated attack.
A return to all-out sectarian violence looks unlikely, but the possible fall of Syria's Assad worries Iraqi Shi'ite leaders who fear that a hardline Sunni government could come to power instead, emboldening Sunni militants in Iraq.
Already, Baghdad says that seasoned al Qaeda fighters are crossing the 680 km (422 mile) border into Syria to liaise and conduct attacks on Assad's government. That hands Islamic State of Iraq new legitimacy in the eyes of some Sunnis, experts say.
Along Iraq's western frontier with Syria, near Albu Kamal, unrest across the border has fired up sympathies in a Sunni heartland with shared tribal and family ties.
Al Qaeda influence is strong in some remote border villages, and Iraqi forces skirmish daily with smugglers and insurgents sending fighters and weapons into Syria, said one senior Iraqi security official.
"The religious legitimacy of the Syria war and the increase of funding and fighters almost unquestionably benefits Al Qaeda in Iraq," said Seth Jones, a counter-terrorism expert at Washington's RAND Corporation and an author on al Qaeda. "It is heavily involved in overseeing the war in Syria."
