The proposed withdrawal would reduce the number of U.S. troops in Iraq to about 130,000 - the same as before the "surge" earlier this year aimed at reducing sectarian violence.
Congressional Democratic leaders criticized Mr. Bush's plan after a meeting with the president Tuesday. House Speaker Nancy Pelosi said it was "an insult to the intelligence of the American people."
General Petraeus and Ryan Crocker, the U.S. ambassador to Iraq, testified before House and Senate committees earlier this week. General Petraeus says the troop increase has led to decreased violence in Iraq, but he and Crocker cautioned against a premature withdrawal of U.S. forces from Iraq.
Iraq's national security advisor, Muwaffaq al-Rubaie, told reporters Wednesday that the number of U.S. troops could be reduced to 100,000 by the end of 2008. He says it would depend on the security threat within and outside the country, and the readiness level of Iraqi security forces.