Iraqis check on a destroyed Sunni mosque Saturday in Basra, Iraq, 340 miles southeast of Baghdad. Bombers loaded into pickup trucks pulled up to the al-Ashrah al-Mubashra mosque in Basra's al-Hakimiya district at dawn Saturday, residents in nearby houses said. Minutes after they left, a huge explosion tore through the building, leveling it completely.

Baghdad, Iraq ? Security forces in Baghdad have full control in only 40 percent of the city five months into the pacification campaign, a top American general said Saturday as U.S. troops began an offensive against two al-Qaida strongholds on the capital’s southern outskirts.

The military, meanwhile, reported that paratroopers had found the ID cards of two missing U.S. soldiers at an al-Qaida safe house 75 miles north of where they were captured last month, but there was no sign of the men. The house contained computers, video equipment and weapons.

Lt. Gen. Raymond Odierno said American troops launched the offensive in Baghdad’s Arab Jabour and Salman Pac neighborhoods Friday night. It was the first time in three years that U.S. soldiers entered those areas, where al-Qaida militants build car bombs and launch Katyusha rockets at American bases and Shiite Muslim neighborhoods.

The overall commander in Iraq, Gen. David Petraeus, said during a news conference with visiting Defense Secretary Robert Gates that the operation would put troops into key al-Qaida-held areas surrounding Baghdad.

Odierno said there was a long way to go in retaking the city from Shiite Muslim militias, Sunni Arab insurgents and al-Qaida terrorists. He said only about “40 percent is really very safe on a routine basis” – with about 30 percent lacking control and a further 30 percent suffering “a high level of violence.”

The U.S. ground forces commander discussed the new offensive and the security situation in an interview with two reporters as he visited an American outpost near the main market in the capital’s southern Dora district, a major Sunni Arab stronghold.

“There’s about 30 percent of the city that needs work, like here in Dora and the surrounding areas,” Odierno said. “Those are the areas that we consider to be the hot spots, which usually have a Sunni-Shiite fault line, and also areas where al-Qaida has decided to make a stand.”

With Baghdad and Basra – the country’s second largest city and gateway to the Persian Gulf – under curfew, violent deaths were down dramatically Saturday. Only three people were reported to have been killed or found dead in sectarian violence.

The U.S. military revealed that identification cards belonging to the two missing soldiers were found June 9 near Samarra but said no one was in the safe house. Troops approaching the building came under fire from nearby trees, suffering two wounded before air support intervened, the statement said.

Spc. Alex R. Jimenez and Pvt. Byron Fouty were snatched in a raid on their 10th Mountain Division unit on May 12 near Youssifiyah. The body of a third soldier taken in the raid, Pfc. Joseph Anzack Jr., was found floating in the Euphrates River. Four other U.S. soldiers and an Iraqi translator were killed in the May 12 ambush.

The Islamic State of Iraq, a front group for al-Qaida, claimed in a video posted on the Internet this month that all three missing soldiers were killed and buried. The militants showed images of the military IDs of Jimenez, 25, of Lawrence, Mass., and Fouty, 19, of Waterford, Mich., but offered no proof they were dead.

On Saturday, attackers blew up the al-Ashrah al-Mubashra mosque in Basra at dawn, residents in nearby houses said. As they were leaving, the bombers wrote graffiti on the complex’s outer wall with the names of revered Shiite saints, witnesses said. No injuries were reported.