BAGHDAD, Feb 27 (Reuters) - A controlled blast by U.S. soldiers near a soccer field in the Iraqi city of Ramadi on Tuesday slightly wounded 30 people, including nine children, a spokesman for the U.S. military said. Police and a local tribal leader in Ramadi earlier said a bomb attack near a soccer field killed 18 people, mostly children. Major Jeff Pool told Reuters the U.S. military was unaware of the attack described by Iraqi officials, saying: "I can't imagine there would be another attack involving children without our people knowing." He said the wounded had cuts and bruises, adding there had been no deaths from the controlled blast.