The U.S. military says more than 500 insurgents in central Iraq have surrendered their weapons and joined the reconciliation process since last month.

A statement Wednesday says 506 former fighters in Iraq's Balad region signed cease-fire agreements and gave up their stock of rockets, grenade launchers, and mortar rounds. The statement says more than 100 of the surrendered fighters have also agreed to stand trial for outstanding criminal charges against them.

A U.S. commander in the region, Lieutenant Colonel Bob McCarthy, called this a key step in re-integrating the former insurgents into their communities.

Iraqi man grieves after two mortar rounds hit a busy street in the central Baghdad area of Karrada, 11 Jun 2008

Also Wednesday, Iraqi officials say a roadside bomb killed at least five people and wounded 10 others in the mostly Shi'ite Kadhimiya district of Baghdad.

The U.S. military also says coalition forces detained a suspected Iranian-trained bomb expert in a raid Wednesday on his home southeast of Baghdad. A statement says the man is believed to have traveled to Iran several times for explosives training.

In other news, Iraq's ambassador to Iran said a bomb was found in front of his home in Tehran on Tuesday. Mohammad Majid al-Sheikh told media an explosive package was planted by people trying to harm Iraqi-Iranian relations.

However, Iran's official news agency (IRNA) quoted an Iranian Foreign ministry official as saying the package was not a bomb, but was a package containing "normal material."

Iraqi Prime Minister Nouri al-Maliki ended a three-day visit to Iran on Monday.