Tensions are high in one of the world's most strategic regions, after attacks on two tankers near the Persian Gulf. The United States claims Iran carried out the suspected coordinated attack on the Japanese- and Norwegian-owned ships. Iran's foreign minister denies it, calling the accusations part of a plot.

Thursday's incident follows similar coordinated attacks less than a month ago that targeted four tankers. Iran denies involvement in that incident, too.

The waterways in the region are crucial to the global transportation of oil and gas: A third of all shipped oil comes through the area. And because the Strait of Hormuz, the narrow waterway near where the attack took place, is right off the coast of Iran, it's a point of leverage for the country. Iran has repeatedly threatened to cut off this vital artery whenever there is a dispute with the U.S. or its regional allies, such as Saudi Arabia and the United Arab Emirates.

As CBS News reported in early June, the admiral of the USS Abraham Lincoln says one of their primary missions is to safeguard the free flow of commerce through this region. The Lincoln was sent specifically because of perceived threats from Iran -- but it hasn't proven to be much of a deterrent.

The U.S. is now pointing to a new video, released overnight, that American officials say shows an Iranian patrol boat coming alongside and removing an unexploded mine from one of the tankers' hulls.

Officials say other mines planted by Iran did explode – leaving one tanker so badly damaged it was in danger of sinking, and the other in danger of drifting into Iranian waters.

"This was actually a fairly high skilled attack by a small boat coming alongside the ship, attaching a limpet mine, or two, or three to the ship, and then making its escape in time in order to avoid the explosion," said CBS News consultant and retired admiral Sandy Winnefeld.

But the owner of one of the tankers says the crew saw "flying objects" before the attack, suggesting mines were not the cause.

Iran says it is in charge of maintaining security in the Strait of Hormuz, and that the U.S.' accusations were alarming. But due to U.S. sanctions on oil exports, Iran is fighting for its economic life -- and if the nation is responsible for the attack, it could be sending a message to other countries in the world that it still has the power to put their oil supplies at risk. It's possible that their hope is to create enough uncertainty that other countries will push the U.S. to ease off.

Regardless of how the attack occurred, the bottom line is the same: more instability in the Gulf region.

"It's not going to help things at all," Winnefeld said. "And when there's less [stability] in the Gulf region, for Americans that means potentially higher prices at the gas pump and the potential for conflict should this escalate."