(New throughout with fresh quotes from U.S. military) By Alister Bull BAQUBA, Iraq, June 24 (Reuters) - U.S. troops hoping to directly confront al Qaeda militants in a major offensive in the Iraqi city of Baquba instead found themselves "swimming through a minefield", a senior officer said on Sunday. The operation in and around Baquba, capital of volatile Diyala province, is in its sixth day and is a major part of one of the biggest offensives by U.S. and Iraqi forces against the Sunni Islamist group in Iraq since the March 2003 invasion. Some U.S. officers said they believed the initial combat phase of the offensive is nearly complete and any militants left could be confronted in the next 24 hours. Hundreds of militants were thought to be still holed up in Baquba's western districts. But others believe many al Qaeda fighters left Baquba after getting clear signals from U.S. commanders who have said for some time that the city was high on their list of priorities. "It's frustrating. You set up something that you know will work ... now we know that most of the al Qaeda enemy got away," said Captain Julian Kemper. "Our purpose was not to push them out somewhere else. It was to end it here." Lieutenant-General Ray Odierno, the deputy U.S. commander in Iraq, has said there was little doubt al Qaeda knew that a major offensive was coming. "They watched the news. They understood we had a surge, they understood Baquba was designated as a problem area," he told Pentagon journalists on Friday. Colonel Steve Townsend, commander of the 3rd Stryker Brigade, said the latest intelligence indicated some fighters were still inside an American cordon, which has been steadily tightened since the operation began. The campaign in Diyala, north of Baghdad, as well as offensives in other regions around the capital, is expected to last several weeks. After heavy street fighting on the first day, Operation Arrowhead Ripper in Baquba has shifted to the slow and dangerous job of clearing scores of buried bombs and booby-trapped houses. BOOBY-TRAP A U.S. jet dropped a precision-guided bomb on one booby-trapped house, setting off a massive secondary explosion. "Even though we're not fighting an enemy soldier, we are swimming through his minefield," Townsend told Reuters. He expected the combat phase of the operation in Baquba to be over in the next 24 to 48 hours as his men re-checked areas to make sure they had not missed any concealed bombs. Barriers and checkpoints, manned by Iraqi security forces, were being put up around three of the most troubled districts in west Baquba to prevent al Qaeda slipping back into the city. Baquba is an al Qaeda stronghold that has also become a sanctuary for militants escaping a security crackdown launched in Baghdad in February. Tens of thousands of U.S. and Iraqi soldiers are engaged in the simultaneous offensives in and around Baghdad to deny al Qaeda sanctuary in farmlands and towns from where they launch car bombs and other attacks in the capital and elsewhere. In Operation Marne Torch, an offensive targeting al Qaeda in Baghdad's southern "beltlands", Major-General Rick Lynch said 12 insurgents had been killed and 142 detained. U.S. and Iraqi forces say they have killed 90 al Qaeda fighters around Baghdad, 55 of them in the Baquba operation. With more U.S. soldiers engaged in offensives around the country the death toll for U.S. forces has begun to rise in June after hitting a two-and-a-half year monthly high in May of 126, the third highest monthly total since the start of the war. Eighty U.S. soldiers have been killed so far in June, 28 of them in the past week. (Additional reporting by Dean Yates, Paul Tait in Baghdad)
