A U.S. soldier was killed in Iraq by small arms fire while manning a traffic control checkpoint at al Qaim on the Syrian border, the U.S. military said Monday. It said a number of attackers pulled up at the checkpoint late Sunday in a vehicle and asked for help for a person in the car they said was ill. Two people armed with pistols got out and shot the soldier, it said. Soldiers at the checkpoint returned fire, killing one assailant, and capturing a second. At least one other assailant fled in the vehicle, the U.S. military statement said. A search was under way for the attackers after the shooting, the latest in a spate of attacks on U.S. soldiers following the U.S.-led war against Iraq that toppled Saddam Hussein. **Bloodshed Follows US Troops*** An Iraqi gunshop owner identified as Mehmid Mutlag, 36, was shot dead by a US patrol in Falluja after soldiers mistook him for an armed assailant, witnesses said. Mutlag's death came just a day after US troops killed another Iraqi after coming under fire on the town's northern outskirts. US soldiers also came under attack Friday in Fallujah when a rocket-propelled grenade was fired at a US armored vehicle, said a resident. Six people, including a local Baath Party leader, have been detained in the northern Iraqi city of Mosul on suspicion of planning attacks on US troops, coalition ground forces said. Meanwhile, top US officials insisted they will find evidence Iraq was developing nuclear, biological and chemical weapons, despite growing doubts in many quarters about the existence of such programs. "I believe we will find them," US national security adviser Condoleezza Rice told NBC's "Meet the Press." Secretary of State Colin Powell stood by his February statement to the UN Security Council, in which he detailed US claims that Iraq was hiding its weapons from UN inspectors. "Not only have I been studying this for many, many years, but, as I prepared that statement, I worked very closely with the Director of Central Intelligence, George Tenet," Powell told the "Fox News Sunday" program. He said his statement had been vetted thoroughly by all of the analysts working on the matter and he had spent four days and nights at CIA headquarters, making sure that data in his speech were supported by intelligence information. "Because it wasn't the president's credibility and my credibility on the line," Powell said. "It was the credibility of the United States of America." But Washington has come under mounting criticism over the failure of US-led troops in Iraq to find the weapons. US lawmakers have called for an investigation into whether the administration distorted intelligence information in order to justify military action. Critics claim Bush, Defense Secretary Donald Rumsfeld and other top aides exaggerated Saddam's arsenal in order to persuade the US public to support the war. **PHOTO CAPTION*** US soldiers restrain an Iraqi pensioner May 18, 2003 (AP Photo/Murad Sezer, File)