WASHINGTON, March 30 (Reuters) - The U.S. military said on Friday it agreed 15 British naval personnel were operating in Iraqi waters when detained by Iran a week ago, but would not say whether the United States had independent information to confirm that assessment. "We agree with the British that the Iranian claims are not credible," said Maj. Gen. Michael Barbero, deputy director for regional operations in the Joint Staff at the Pentagon. Barbero said the U.S. military's assessment was based on information the British had shared about the location of the ship and British forces in relation to Iraqi waters. When pressed on whether the United States had independent information, Barbero declined to comment. "I'm telling you that based on where we are in the situation I probably shouldn't say anything else," he told reporters. "As you understand, it's a very delicate situation at a critical stage," Barbero said. Barbero's comments are the first statement the U.S. military has made about the location of its closest ally's forces when detained by Iran. Senior defense officials, including Defense Secretary Robert Gates, have declined to comment with any specificity about the situation.