Another US soldier was killed in Iraq, taking the US troop combat toll to nearly 200 since major hosilities were declared over, while the US military said a deadly tanker truck explosion in Baghdad was caused by an accident, not a bomb. The latest US troop fatality came in an ambush Wednesday night on a vehicle patrol in the capital's Karkh district, a US military spokeswoman said, adding that another soldier and an Iraqi interpreter were also wounded. The US military announced Sunday that it had captured former Iraqi president Saddam Hussein a day earlier, sparking an upsurge in violence north and west of the capital since then as well as numerous pro-Saddam demonstrations. In Samarra, US forces, backed by armoured vehicles and attack helicopters, launched Operation Ivy Blizzard against insurgents during which they arrested 12 suspects, the army said. The raid came two days after a US patrol was ambushed in the town, between Tikrit and Baghdad, and claimed to have killed 11 Iraqis. The military also said that the explosion of a tanker truck in Baghdad Wednesday that killed 10 people and wounding 15, was not due to a bomb. "It was just an accident yesterday. It was a fuel truck that got hit by another truck," a US spokeswoman said. Hours after the blast, Iraqi police had said the truck was loaded with explosives, describing it as a "terrorist act" that targetted civilians. Iraqi leaders brushed aside calls for an international trial of the captured dictator, saying he would be tried in Iraq under terms set by a new government due to take power July 1. Muaffak al-Rubaie, a member of Iraq's interim Governing Council, said Saddam was in Baghdad and would remain there to be put on public trial by a new Iraqi government set to take over July 1. Iraqi and US leaders have rebuffed calls for Saddam to be tried before an international tribunal -- a position that won support from French Foreign Minister Dominique de Villepin, who said it was up to Iraqis to judge Saddam "while respecting the law and doing so impartially." US President George W. Bush has called for Saddam to face the "ultimate penalty," in contrast to other supporters of an Iraqi trial for the former dictator who insist he should not face execution. Controversial French lawyer Jacques Verges, who has defended clients including Gestapo chief Klaus Barbie, has confirmed that he was willing to act for the captured Iraqi leader when he comes to trial. In Washington, Iraqi legal experts warned convicting Saddam might be more difficult than expected. "It is one thing to say what we all know about what Saddam did. But it's another to prove it in a court of law," warned Kanan Makiya, founder of the Iraq Memory Foundation, one of the groups helping to draw up a new Iraqi constitution. "We don't have a smoking gun to convict Saddam. We will need witnesses, documents." And in Tokyo, the Japanese government said Thursday it would send an advance air force unit by the end of the year to start its mission in Iraq. **PHOTO CAPTION*** A U.S. soldier applies camouflage face paint before going on a mission in Samarra, Iraq, on Wednesday, Dec. 17, 2003. (AP Photo/Stefan Zaklin, Pool)