Navy officials have lost contact with two U.S. Marine jets from the USS Carl Vinson (search) aircraft carrier flying in support of operations in Iraq, the U.S. military said Tuesday.

The status of the two U.S. Marine F/A-18 Hornet (search) aircraft and their crew was not immediately known, the military said in a statement.

Defense officials told FOX News the jets may have crashed into each other while flying with night vision.

Contact was lost at 10:10 p.m. Monday, the statement said. There were no initial indications of hostile fire in the area at the time.

Search efforts were underway, the military said. No further information was released.

Navy officials at the Pentagon did not release any information beyond the military statement.

Wave of Bloodshed

At least 23 Iraqis were killed Monday, including eight soldiers cut down by an attacker who blew up a truck at a checkpoint south of the capital, and six civilians caught in a car bombing that set fire to a Baghdad apartment building. An American and a British soldier were also killed in separate roadside bombings.

In New York, U.N. Secretary-General Kofi Annan (search) issued a statement strongly condemning the "cruel and heartless" violence apparently aimed at undermining Iraq's newly formed government.

The skyrocketing attacks are blamed on an insurgency believed largely made up of members of Iraq's Sunni minority, who dominated for decades under Saddam Hussein but were excluded from meaningful positions in a partial new Cabinet announced Thursday.

On Monday, a bomber exploded a truck at an Iraqi checkpoint near Youssifiyah, 12 miles south of Baghdad, killing eight soldiers and wounding 20, said Iraqi army Capt. Qassem Sharif.

Two car bombs in Baghdad killed at least nine more Iraqis. One exploded in an upscale shopping district in southern Baghdad and set fire to a six-story apartment building. Six civilians were killed and seven wounded in the explosion, which missed a police patrol, said police Lt. Col. Salman Abdul Karim al-Fartosi. As firefighters fought the blaze, thick black smoke and flames rose from the ground floor.

The other car bomb exploded near a passport office in eastern Baghdad, killing three Iraqis, including two policemen, and wounding six, three of them also officers, said police Lt. Col. Hassan Chalob.

An American soldier from the 1st Corps Support Command was killed and another wounded when a roadside bomb detonated near their vehicle during a patrol south of Baghdad airport, the U.S. command said. At least 1,581 members of the U.S. military have died since the beginning of the Iraq war in March 2003, according to an Associated Press count.

Another American military patrol and a top Iraqi security official narrowly escaped two other bombings, U.S. and Iraqi officials said.

The British soldier from the 12th Mechanized Brigade died of injures inflicted by a roadside bomb in Amarah, 180 miles southeast of Baghdad. A total of 87 British troops have been killed in Iraq since the start of the war.

In northern Iraq, a car bomb and another bomb went off in quick succession near an American patrol in the Mosul area, the U.S. military said. The coordinated attack killed at least two Iraqis and wounded 15, military spokesman Capt. Mark Walter said. Hospital officials, however, said four Iraqis were killed and seven injured.

Two other bomb blasts in Mosul, 225 miles northwest of Baghdad, caused minor injuries to U.S. soldiers, and a third one targeting Iraqi soldiers killed one civilian, Walter said. Gunfire in another attack killed another civilian, he said.

Coalition forces have hit back in recent weeks, detaining suspected militants and confiscating hidden arms caches. U.S. and Iraqi forces have detained 84 suspects in the Baghdad area since Sunday, the U.S. military said. An additional 52 suspects were detained Monday in a joint operation in the Diyarah area, south of the capital, the military said.

FOX News' Bret Baier, Andrew Hard and The Associated Press contributed to this report.