President George W Bush called on his foes in Congress and the American people to support sending 21,500 more troops to Iraq, as a UN official warned it was "sliding into the abyss of sectarianism."
"Our country is pursuing a new strategy in Iraq and I ask you to give it a chance to work," Bush said in his annual State of the Union address on Tuesday, against a backdrop of slumping ratings as public anger grows over the nearly four-year war.
Bush, battling criticism over the rationale for the war and his strategy, faces strong opposition from Democrats who now control both houses of Congress and dissent within his own Republican Party over his plan for reinforcements in Iraq.
"It is still within our power to shape the outcome of this battle. So let us find our resolve and turn events toward victory," he said.
Bush proposed a bipartisan council of leaders in Congress to consult on Iraq and the broader war on terrorism, but much of the 50-minute speech focused on his domestic agenda.
A day after bombers killed 88 people in Baghdad's bloodiest attack this year, gunbattles and the crash of a US civilian helicopter in the center of the capital kept nerves on edge.
The deaths of two American soldiers took the toll to 29 in the past three days. More than 3,000 US soldiers and tens of thousands of Iraqis have been killed since the 2003 invasion.
Before Bush outlined his latest plan to clear Baghdad of Sunni and Shi'ite militants, his choice to take command of the war, Army Lt Gen David Petraeus, told a Senate committee the situation in Iraq was dire but not impossible.
"The way ahead will be very hard," Petraeus said. "But hard is not hopeless."
Some Democrats want Bush to withdraw some of the 134,000 US troops from Iraq in four to six months. Bush and American commanders say the new plan for Baghdad will involve more Iraqi forces than one last year, raising the chances of success.
Many Americans are unconvinced. A Washington-Post/ABC News poll gave Bush an approval rating of just 33 percent and said 65 percent of those surveyed oppose the troop increase, up from 61 percent immediately after he outlined the strategy on Jan 10.
"Save the country"
UN envoy Ashraf Qazi condemned Monday's bombings, urging Iraq's political and religious leaders to "save the country from sliding further into the abyss of sectarianism."
Prime Minister Nuri al-Maliki, from Iraq's Shi'ite Muslim majority, blamed the blasts on followers of Saddam Hussein, whose botched execution last month angered many among his fellow minority Sunni Arabs.
The U.S. military said Iraqi and American troops were taking a "balanced approach" in fighting Shi'ite and Sunni insurgents, after Sunnis accused Maliki's government of failing to crack down on Shi'ite militias loyal to his allies.
Some 600 members of radical Shi'ite cleric Moqtada al-Sadr's Mehdi Army were in custody, the military said.
Bush warned in his speech of an "escalating danger" from Shi'ite extremist groups that he said were as big a threat to the United States as the Sunni militants of al Qaeda who carried out the Sept. 11 attacks in 2001.
"Many are known to take direction from the regime in Iran, which is funding and arming terrorists like Hezbollah," he said. "The Shia (Shi'ite) and Sunni extremists are different faces of the same totalitarian threat."
Maliki has pledged to tackle all militants in a coming crackdown. Senior Shi'ite allies say it may be the last chance to avert the collapse of the new state, which has given Shi'ites the upper hand in Iraq for the first time.
In raids apparently aimed at Sunni insurgents on Tuesday, the US military said it killed 16 guerrillas in and around Baghdad and Anbar province in western Iraq.
Al Qaeda deputy leader Ayman al-Zawahri mocked Bush's Iraq plan and said militants could wipe out the entire US army.
"Why send 20,000 only? Why not send 50 or 100,000?" he said in an Internet video. "Aren't you aware that the dogs of Iraq are pining for your troops' dead bodies?"