Transcript for U.S. Warships Defy Iran's Warnings
As this tension rises with the Ron US naval forces are watching the skies above in the water below. In the stretch known as the straight a form was just 21 miles across. 15. Of the world's oil supply has to pass through this gateway 10% of all the oil used here in America. And as we said today three US warships navigated those waters defying threats and warnings from Iran. And ABC's senior foreign affairs correspondent Martha Raddatz was on board. It was just after dawn when that three US warships in the carrier strike group. Began the long -- transit through the Strait of Hormuz. We're just months ago the Iranians warns US warships not to return. Do you want to be always had a -- state of readiness we are on the lead ship. The US says -- a destroyer with dozens of missiles and machine guns. On the bridge the concentration. Is intent deserves credit -- Surveillance extract and everything that moves that the Iranians were silently shadowing us as well. The Ronnie -- navy vessels -- and a patrol planes flying overhead. This shipping -- itself is only about two miles wide so there is very little room to maneuver that's the massive aircraft carrier USS Abraham Lincoln just behind me. -- -- -- crossing the captain was called to the deck. A small craft was approaching -- similar to those of Iran's revolutionary guard navy that have been harassing US ships for months. ServiceMaster Lindsay and you're Catholic intentions right identify that group quickly -- -- it was a smuggler would eventually turned away. Naval commanders say these -- it's our routine. But they also fear that miscalculations. On either side could threaten not only these ships. But closed -- this waterway and put the world's economy at stake. Martha Raddatz ABC news aboard the US -- stare --
This transcript has been automatically generated and may not be 100% accurate.