The U.S. State Department's chief of diplomatic security has announced his resignation, a day after Secretary of State Condoleezza Rice ordered new measures to improve government oversight of private security guards in Iraq.

Richard Griffin, who served as Assistant Secretary of State for Diplomatic Security, did not mention the security firm Blackwater USA in his resignation letter.

Blackwater guards are accused of deliberately killing 17 people in Baghdad on September 16. The security firm says it responded lawfully to an attack on a U.S. diplomatic convoy.

Rice appointed a panel to examine the role of security firms in Iraq following the shooting. The new oversight measures she ordered Tuesday were recommended by the panel.

The developments come as an Iraqi official says his government plans to submit a draft law that ends the immunity for foreign security contractors in Iraq. The immunity was granted in a 2004 directive by Paul Bremer, head of the Coalition Provisional Authority.

In Iraq violence Wednesday, officials say two nearly simultaneous bomb blasts killed at least eight people in a mainly Shi'ite area southeast of Baghdad.

Police say the explosions in Jisr Diyala wounded more than 20 people Wednesday morning in a busy market area where people had gathered for transport to their jobs in the Iraqi capital.

Separately, the U.S. military says a coalition soldier died of wounds from a mine explosion Wednesday. It says three coalition soldiers were injured in the blast in Salah ad Din.

Some information for this report provided by AP and AFP.