Iraq troop numbers to stay at 138,000
U.S. launches offensive in Diwaniyah
Marines ride past a guard tower at the Abu Ghraib prison Tuesday.
Brig. Gen. Janis Karpinski, former military police commander at Abu Ghraib, says she had "absolutely no knowledge" of prisoner abuse.
Iraqi insurgents launch their heaviest attacks on U.S. troops in Najaf since last month.
Two former Iraqi prisoners talk about their treatment at Abu Ghraib prison.
CNN's Ben Wedeman looks at how the coalition is speeding the training of Iraqi troops.
(CNN) -- U.S. troop strength in Iraq will remain at about 138,000 until the end of 2005, Pentagon officials said Tuesday.
The Pentagon plans to deploy 10,000 active-duty soldiers and Marines, and 37,000 National Guard and Reserve troops to Iraq to maintain the current force level in the country, officials said.
Replacement troops are being lined up to relieve those whose tours of duty were extended last month because of intensified fighting, Defense Secretary Donald Rumsfeld said Tuesday.
The number of troops was supposed to fall to around 115,000, but Gen. John Abizaid, head of the U.S. Central Command, which includes forces in Iraq, asked to keep troop numbers at about 135,000 in April, initially on a 90-day extension.
"We are identifying and preparing to deploy forces to replace those individuals," Rumsfeld said. "Recently I approved deployment of approximately 10,000 replacement personnel. Other units are now being identified and will be approved in the coming days."
The active-duty troops will include about 5,000 soldiers and 5,000 Marines.
Marines from Camp Pendleton, California, and Camp Lejeune, North Carolina, will leave for a yearlong tour of duty in Iraq in four to six weeks.
National Guard and Reserve forces are being called to active duty to replace the 20,000 troops who recently had their terms in Iraq extended by 90 days.
They will relieve troops from the 1st Armored Division and 2nd Armored Cavalry Regiment, which originally had been scheduled to rotate out of Iraq last month.
More than 120 U.S. troops have died since early April in an upsurge in violence in Iraq.
Seven hundred sixty American troops have died since the U.S.-led invasion last year -- 552 of them in hostile action.
Fighting around Najaf
U.S. forces launched a major operation in southern Iraq late Tuesday, taking over the office of radical Shiite cleric Muqtada al-Sadr in Diwaniyah, a town along the Euphrates River about 40 miles east of the holy city of Najaf.
It was the biggest operation against al-Sadr's militia since the 2nd Armored Cavalry Regiment arrived in the region in force last week, military officials said.
They said an AC-130 gunship fired 40 mm rounds on the building. The military said its reconnaissance indicated more than a dozen militia members armed with AK-47s and rocket-propelled grenades were inside.
The militants apparently escaped before it was struck, the officials said.
One of the 40 mm rounds hit a nearby house, setting it on fire. It was not clear if anybody was wounded inside.
One U.S. soldier at a checkpoint was shot in the abdomen when a gunman opened fire from a vehicle, officials said. The soldier's unit returned fire on the car, destroying it and killing those inside.
Al-Sadr, who is wanted by an Iraqi court in connection with the killing of a rival cleric, is believed to be holed up in Najaf with members of his militia, the Mehdi Army.
The militia launched an uprising last month against the U.S.-led coalition and its supporters in Baghdad's Sadr City neighborhood and Iraq's southern cities.
Earlier in the day, two U.S. soldiers were wounded near Najaf's airfield when a convoy came under attack, U.S. military officials said.
U.S. forces were moving to set up a checkpoint at the airfield when a rocket-propelled grenade was fired at a tank.
The move to occupy checkpoints throughout the city followed a barrage of insurgents' mortar and small-arms fire Monday, an American commander said.
The U.S. base in Najaf came under almost steady attack by suspected members of al-Sadr's militia.
Report finds 'grave breaches'
The Bush administration moved aggressively Tuesday to signal it took seriously abuse at Abu Ghraib prison in Iraq as detailed by a Pentagon investigation.
According to a report made available to CNN, the investigation found that U.S. soldiers committed "egregious acts" and "grave breaches of international law."
The report said key senior leadership failed to comply with established regulations, policies and command directives in preventing detainee abuses at Abu Ghraib and Camp Bucca from August to February. (Full story)
Six soldiers have been criminally charged in the case in Iraq and six others have been reprimanded, with two of those relieved of duty.
The report said that the abuse included threatening detainees with a pistol and with military dogs, sodomizing a prisoner with a chemical light and perhaps a broomstick, forcing naked prisoners into compromising positions and accusing them of being homosexuals.
Speaking from the United Nations, Secretary of State Colin Powell condemned such acts as "immoral" and "despicable."
National security adviser Condoleezza Rice gave television interviews to three Arab networks -- Al-Arabiya, Al-Jazeera, and the Lebanese Broadcasting Corp. -- indicating the White House appears to be keenly aware of the outrage around the world, particularly among Muslims.
Rumsfeld said he would take "all measures necessary" to ensure that such abuse of detainees "does not happen again." (Full story)
The chairmen of the Senate Armed Services and the Senate Intelligence Committee both said Tuesday that their panels would hold hearings on the matter.
Some lawmakers complained the Pentagon did not brief Congress about the situation and that the report of the abuses was not available to them until Tuesday. (Full story)
CNN's Jane Arraf, Arwa Damon, Guy Henshilwood, Joe Johns and Mike Mount contributed to this report.