April 10 (Bloomberg) -- President George W. Bush today will announce a reduction in Army combat tours to 12 months from the current 15 months and accept General David Petraeus's plan to suspend further force reductions in Iraq beyond July.

The 12-month tours will apply to units sent to Iraq as of Aug. 1 or later. The move is aimed at reducing stress on the troops and their families, White House Press Secretary Dana Perino told reporters.

Bush will make the announcements in a 12- to 15-minute speech on Iraq this morning from the White House. Petraeus, the top U.S. commander in Iraq, testified before Congress this week that progress in Iraq is too ``fragile and reversible'' to allow U.S. troop levels to fall below about 140,000 before September at the earliest.

Petraeus recommended the troop levels be held steady for a 45-day period evaluation after the final brigade from last year's buildup of forces in Iraq is withdrawn in July.

``The president thinks that is prudent and responsible, and he will accept that,'' Perino said.

The U.S. is withdrawing about 21,500 of the 30,000 soldiers and Marines added to Iraq as part of surge that Bush ordered in January 2007.

For the past two years, Bush has been under pressure from congressional Democrats to set a timetable for withdrawing U.S. forces from the country. Lawmakers also have begun calling for the Iraqi government to use more of its oil revenue to pay for reconstruction and take a greater role in security operations.

Units deployed to Iraq and Afghanistan have been on the extended 15-month tours since April 2007.

Admiral Michael Mullen, chairman of the Joint Chiefs of Staff, told Congress earlier this month that the military can't meet all its needs in Afghanistan because of the burden imposed by the U.S. presence in Iraq.

The U.S. has about 31,000 troops in Afghanistan, and Mullen said the U.S. needs to add about 3,000 personnel to train Afghan forces and another 7,000 to fight a resurgence of the Taliban.

To contact the reporter on this story: Catherine Dodge in Washington at cdodge1@bloomberg.net

Last Updated: April 10, 2008 10:58 EDT