WASHINGTON, Jan. 10 (Xinhua) -- U.S. President George W. Bush said Wednesday night that he took responsibility for "mistakes" made in Iraq.

    "The situation in Iraq is unacceptable to the American people and it is unacceptable to me," Bush said in a nationally-televised address.

    "Our troops in Iraq have fought bravely. They have done everything we have asked them to do. Where mistakes have been made, the responsibility rests with me," he said.

    The president also said his country's commitment to Iraq is not open-ended.

    "I have made it clear to the prime minister (Nouri al-Maliki) and Iraq's other leaders that America's commitment is not open-ended," he said.

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

    The president said failure in Iraq would be a disaster for the United States.

    "The consequences of failure are clear: radical Islamic extremists would grow in strength and gain new recruits. They would be in a better position to topple moderate governments, create chaos in the region and use oil revenues to fund their ambitions," Bush said.

    The president said if the United States failed in Iraq, "Iran would be emboldened in its pursuit of nuclear weapons. Our enemies would have a safe haven from which to plan and launch attacks on the American people."

    The most urgent priority for success in Iraq, he said, was security, especially in Baghdad, the Iraqi capital.

    According to Bush, 80 percent of Iraq's sectarian violence occurred within 48 km of the capital, and violence "is splitting Baghdad into sectarian enclaves and shaking the confidence of all Iraqis.

    "Only the Iraqis can end the sectarian violence and secure their people. And their government has put forward an aggressive plan to do it," he said.

    U.S. forces failed to secure Baghdad for two principal reasons, he said. One reason was that there were not enough Iraqi and American troops to secure places "cleared of terrorists and insurgents" and the other was that there were too many restrictions on the U.S. troops in Iraq.