An American working as a US government contractor was killed in a rocket attack Tuesday on the heavily guarded Green Zone, the location of the American Embassy in Baghdad, the acting American Ambassador said. "It is with a profound sense of sadness and regret that we announce the loss of a US Government contractor as the result of a rocket attack on the International Zone in Baghdad, Iraq," Charge d'Affairs Daniel Speckhard said in a statement issued late Tuesday. One other contractor was seriously wounded and in stable condition, and three others were slightly wounded, said Lou Fintor, the embassy spokesman. He would not give the nationalities of the wounded. "On behalf of the US Embassy and the entire American community in Iraq, I would like to extend our deepest sympathies to the family and friends of our colleague," said Speckhard, who is standing in as ambassador after the departure Monday of Zalmay Khalilzad.