U.S. officials report they have found the bodies of two American security contractors in Iraq who were kidnapped there more than a year ago.

The Federal Bureau of Investigation announced Monday it had identified the bodies of Ronald Withrow and John Roy Young. Withrow had worked for JPI Worldwide when he was kidnapped in January, 2007. Young was a contractor for Crescent Security Group when he was taken in November, 2006.

The bodies were recovered as the White House announced that 4,000 American military personnel have now been killed during the U.S.-led war in Iraq. The war entered its sixth year on Sunday.

In comments to reporters at the State Department Monday, President Bush expressed his deepest sympathies to the families of the war dead. He vowed to make sure their lives were not lost in vain.

The president participated in a two-hour videoconference Monday with the top U.S. Commander in Iraq, General David Petraeus, and Ryan Crocker, the U.S. Ambassador to Iraq.

Petraeus and Crocker are due to testify in Congress on April 8 and 9. President Bush wants to get their latest thinking on whether to continue withdrawing troops, due to a recent drop in violence, or to take a pause to assess the situation.

A roadside bomb blast in Diyala province Monday killed two Iraqi soldiers and wounded four others.

The estimated number of Iraqi deaths blamed on five years of war ranges from the tens of thousands to the hundreds of thousands.

In addition to the the human loss, the war in Iraq is reported to have cost the United States more than $400 billion.

Some information for this report was provided by AFP, AP.