A potentially serious confrontation is emerging between Iran and the US in the world's busiest oil chokepoint.

On Tuesday, the Iranian navy opened fire on a container ship owned by Maersk and then boarded the ship, according to the Pentagon. The ship was traveling through an internationally recognized shipping lane and flying the flag of the Marshall Islands, a Pacific island nation.

Now a US destroyer, the USS Farragut, is being deployed to the Persian Gulf in an attempt to assist the vessel, a 65,000-ton cargo ship named the Maersk Tigris.

"At first appearance it does seem to be provocative behavior, but again we don't have all the facts yet," Col. Steve Warren, a Pentagon spokesman, told reporters.

The Tigris' bridge officers were "contacted and directed to proceed further into Iranian territorial waters." When the officer on duty declined, the Iranian patrols opened fire. At that point, "The master complied with the Iranian demand and proceeded into Iranian waters," Warren told CNN.

Iran reportedly pulled the ship into Bandar Abbas, a major Iranian port city near the narrowest point in the Strait of Hormuz, the body of water at the mouth of the Persian Gulf through which some 17 million barrels of oil pass each day. That accounts for nearly a third of the world's seaborne oil trade.

The ship was seized under a court order issued by Iran's ports authority, according to the country's Fars news agency. But the company that manages the ship, the Maersk Tigris, told Reuters that it was unaware of such an order.

The US has several military vessels deployed in and around the Persian Gulf. Soon after the ship issued a distress call, the USS Farragut traveled west toward its last known location as the situation developed. First launched in 2005, the Farragut can carry up to 96 missiles and has aided in anti-piracy operations off the coast of Somalia.

The Maersk Line, which owns the ship, is a Copenhagen-based company responsible for 15% of all seaborne freight as of 2011. The vessel is a 750-foot container ship built in 2014. It originated at a port in Saudi Arabia and was reportedly bound for Jebel Ali, outside of Dubai in the United Arab Emirates.

The US Fifth Fleet, which is based in Bahrain, had no comment on the developing situation, according to Reuters.

Details are still scant. But if the Iranian military did harass and open fire on a vessel in internationally recognized trading lanes in the Strait, it could significantly raise tensions with neighboring countries, with potentially serious political and economic consequences.

The USS Farragut. Wikimedia Commons

The potential showdown between a US destroyer and Iranian patrol boats comes just a week after the US dispatched nine vessels to Yemen's coastal waters to counter an increased Iranian naval presence near the troubled Arabian country. US military planners feared that Iranian vessels were providing arms deliveries for Yemen's Houthi rebels, Iranian-allied fighters who deposed the country's internationally recognized government earlier this year.

The potential showdown ended when Iranian vessels left the region on Thursday.

There's another reason the US may be taking this so seriously: While the Marshall Islands is a sovereign nation, the US gained control of the island after Japan's defeat in World War II. Under a 1983 Compact of Free Association with the United States, the US still has "full authority and responsibility for security and defense" of the island chain, according to a US State Department fact sheet.

Michael Kelley contributed to this report.