KABUL (Reuters) - A U.S. air strike called in to suppress an attack in Kabul on Wednesday as Defense Secretary Jim Mattis was visiting the Afghan capital caused a number of civilian casualties, the NATO-led Resolute Support mission said. The air strike was called in to support an Afghan Special Forces unit battling attackers who hit Kabul airport, but it suffered a missile malfunction,  causing several casualties , the statement said. It gave no details. 