The US Navy build-up in the Gulf region was prompted by increasing provocation from Iran, which has carried out war games and tested missiles perilously close to crucial shipping lanes for oil tankers, the top US Navy commander in the Mideast said. Over the past year, Iran brought its war maneuvers "right around the jugular" into busy shipping lanes in the Straits of Hormuz, the narrow mouth of the Gulf through which around two-fifths of the world's oil supplies pass, Vice Adm. Patrick Walsh said in an interview with the Associated Press and several other reporters. During maneuvers, Iranian sailors loaded mines onto small minelaying boats and test-fired a Shahab-3 ballistic missile into international waters, he said. "The Shahab-3 most recently went into waters very close to the traffic separation scheme in the straits themselves. This gives us concern because innocent passage of vessels now is threatened," Walsh said in the interview Monday on the base of the Navy's Fifth Fleet in Bahrain.