ROUGH CUT (NO REPORTER NARRATION) STORY: Iran started on Friday six days of naval drills in the Strait of Hormuz, Iran's English-language broadcasting station Press TV and the country's official IRNA news agency reported. The maneuvers are aimed at showcasing Iran's military capabilities in what is a vital oil and gas shipping route. The "Velayat 91" drills would last until Wednesday across an area of about 1 million square kilometers in the Strait of Hormuz, the Gulf of Oman and northern parts of the Indian Ocean, Press TV reported Sayyari as saying. Iranian officials have often said Iran could block the strait - through which 40 percent of the world's sea-borne oil exports pass - if it came under military attack over its disputed nuclear program. Iran held a similar 10-day drill last December and sent a submarine and a destroyer into the Gulf four months ago just as U.S. and allied navies were conducting exercises in the same waters to practice keeping oil shipping lanes open. A heavy Western naval presence in the Gulf is meant to deter any attempt to block the waterway.