Washington: Top US officials in Iraq will testify on the war for a second day on Wednesday as the Bush administration presses a case against a big troop reduction.

US commander in Iraq General David Petraeus and Ambassador Ryan Crocker are expected to tell Congress that the United States risks losing in Iraq if it withdraws too many troops too quickly.

Petraeus told the Senate on Tuesday he wanted to stop troop withdrawals after a current drawdown ends in July, leaving around 140,000 troops in Iraq.

President George W. Bush has said he would back such a recommendation. The White House said Bush plans to meet members of Congress once Petraeus's testimony is over.

White House spokeswoman Dana Perino said Bush plans to give "a wide-ranging speech on a variety of issues" related to Iraq.

US officials have said Bush is expected to announce, perhaps as soon as Thursday, that US soldiers' tours in Iraq and Afghanistan will be cut back to one year from 15 months.