Washington: US President George W. Bush conceded that efforts to secure Iraq had failed and that he was sending over 20,000 extra troops in a strategic shift to quell sectarian killings and hasten the day when US troops begin coming home.

Bush Wednesday spoke frankly about errors and misjudgements by both his administration and the Iraqi government that have led to chaos in Iraq and undermined US public support.

"Where mistakes have been made, the responsibility rests with me," Bush said in a primetime address from the White House.

Bush's plan was widely viewed as his last real chance at succeeding in Iraq and galvanizing public support for the war, which has claimed the lives of over 3,000 US soldiers and cost more than $430 billion.

"The US military and Iraqi forces have been unable to secure Baghdad because of limitations placed on them by the Iraqi government, but new rules will allow the Americans and Iraqis to be more aggressive," Bush said.

Bush's plan to enlarge the US force has been met by stiff resistance in Congress, where newly empowered opposition Democrats are demanding that US troops begin to be brought home. Opinion polls show most of the American public also opposes a hike, but Bush argued that more forces in the short run could lay the foundation for future withdrawals.

"If we increase our support at this crucial moment and help the Iraqis break the current cycle of violence, we can hasten the day our troops begin coming home," Bush said.

The new strategy includes placing more pressure on the Baghdad Government to end sectarian violence, which has brought the country to the brink of civil war, and emphasises that Iraqi Prime Minister Nuri al-Maliki's Government must take greater responsibility for the country's future.

"I have made it clear to the prime minister and Iraq's other leaders that America's commitment is not open-ended," Bush said.

"If the Iraqi government does not follow through on its promises, it will lose the support of the American people," he said.
 

The phased build-up, which is expected to take several months, will cost an additional $5.6 billion, a senior administration official said. Some 140,000 US troops are already in Iraq.

Democrats plan to call for votes in the US Senate and House of Representatives on resolutions rejecting the surge in troops. Although not binding, the measures would force Bush's Republicans to take a position on the increase. Some Republicans have also expressed reservations about expanding the US presence.

 Under the president's plan, the US will deploy about 17,500 troops in Baghdad to contain sectarian violence, but Iraqi forces will remain in the lead. Bush will order another 4,000 soldiers to al-Anbar province in western Iraq, where al-Qaeda has found refuge.

 
Bush said that the Iraqi government has plans to take responsibility for security by November in all of Iraq's provinces.

The surge of US troops is a notable departure from the advice of his top military officers for Iraq, who have said that an increase would do little to change conditions on the ground.

In preparing to move swiftly on his new plan, Bush announced last week that he was replacing his top military commanders and diplomats in Iraq.
 

The plan includes doubling the size of provincial rebuilding teams in Iraq and pumping more money into the Iraqi economy - more than $1 billion.

"Ordinary Iraqi citizens must see that military operations are accompanied by visible improvements in their neighbourhoods and communities. Al-Maliki's government must move forward on a national reconciliation plan that includes regional elections and an oil law to ensure fair distribution of revenue to Iraq's ethnic and religious groups to help ease tensions between Shias, Sunnis and Kurds," Bush said.

The president said the US would confront Iran and Syria, accusing them of fomenting violence in Iraq by allowing insurgents into the country and supporting attacks on US troops.

Bush acknowledged that his administration was overconfident that Iraqi elections and the formation of a government since 2005 would stabilise the country and usher in the reduction of US forces. Those hopes were dashed by bloodshed between Sunnis and Shias that peaked last summer.

House Speaker Nancy Pelosi, the top congressional Democrat, confirmed that the centre-left congressional leadership would call for a vote on the increase.

"The American people have lost confidence in the president's policy," she said.

Bush argued that a pullout would 'force a collapse' of the Iraqi Government and result in mass killings on an unimaginable scale, instead keeping US troops in the country even longer.