Iraq's Prime Minister Nuri Al-Maliki (R) shakes hands with U.S. Vice President Joe Biden as they pose during Biden's visit to Baghdad January 23, 2010. [Xinhua]

The U.S. government will appeal the dismissal of Blackwater case as demanded by the Iraqi government, U.S. Vice President Joe Biden said in Baghdad on Saturday.

Biden expressed his personal regret for what Blackwater guards committed in 2007, saying the United States insists to put anyone who committed crimes against Iraqi people under questioning, said a statement issued late Saturday by the office of Iraqi President Jalal Talabani after a meeting between them.

Iraq's Prime Minister Nuri Al-Maliki (R) meets with U.S. Vice President Joe Biden (L) during Biden's visit to Baghdad January 23, 2010. [Xinhua]

Blackwater, now called Xe Services, was a private security contractor hired to protect U.S. State Department personnel in Iraq. It was accused by the Iraqi government of using excessive force in Baghdad streets.

On Sept. 16, 2007, Blackwater guards opened fire with automatic weapons and grenade launchers on unarmed Iraqi civilians in Baghdad after a car bomb exploded.

The U.S. government had accused its five guards of causing the deaths of unarmed civilians. However, Ricardo Urbina, a U.S. federal judge, dismissed the charges against the five at the end of last year, claiming incriminating statements were used by federal prosecutors in the case.

The dismissal outraged the Iraqi victims. The Iraqi government said the investigations conducted by the Iraqi authorities confirm clearly that the Blackwater guards committed murder and violated the rule of only using arms under the circumstances of being threatened.

Biden also met with some other senior Iraqi officials. He arrived in Baghdad late Friday in a visit believed to try to help solve a dispute in Iraq over a ban of 511 candidates from running in the country's March parliamentary elections.