The U.S. State Department would not say Friday if it is asking the government of Iran to release a Marshall Islands-flagged cargo ship it seized in the Strait of Hormuz earlier this week.

“We've been working with the Republic of the Marshall Islands and with Maersk to understand the facts of the situation,” said Jeff Rathke, a State Department spokesman. Rathke, though, refused to answer repeated questions on whether the Obama administration had asked Iran to release the M/V Maersk Tigris.

Earlier this week, fast attack craft from Iran’s Revolutionary Guard Corps Navy fired warning shots across the bridge of the M/V Maerk Tigris, while it was transiting the Strait of Hormuz, according to Col. Steve Warren, a Pentagon spokesman. The ship has 24-crewmembers aboard and all remain confined to their cabins under Iranian guard, according to a spokesman for Rickmers Shipmanagement, which operates the vessel.

Iran says it is holding the ship because of a 2005 cargo delivery dispute. This week's incident already has led the U.S. Navy ‎to dispatch ships to accompany U.S.-flagged vessels in the area; further‎, the U.S. has a security agreement with the Marshall Islands, raising questions about whether the U.S. might intervene in this case in a more active way.

According to a statement from Maersk, the dispute occurred in January 2005. Ten containers aboard a Maersk Line vessel on behalf of an Iranian company were delivered to Dubai and later discarded. “The containers were never collected … and after 90 days and in accordance with UAE law, the cargo was disposed of by UAE authorities,” the company said.

An Iranian court is seeking $3.6 million in damages.

When Rathke was asked if the ship was being held for ransom, he answered, “There have been conflicting reports from Iran. They've provided various justifications for this action. So it's not entirely clear the basis on which they've acted.”

The Maersk Tigris remains at anchor south of Bandar Abbas, home to Iran’s largest Navy base, outside the Strait of Hormuz, according to marinetraffic.com, a shipping website that tracks merchant vessels.

Secretary of Defense Ash Carter, meanwhile, approved a U.S. Central Command recommendation Thursday for U.S. warships in the Persian Gulf to begin accompanying U.S.-flagged vessels.

Warren told reporters Friday that four-U.S. flagged vessels have since been “accompanied” in the past 24 hours. Warren explained the difference between accompanying and escorting merchant vessels -- U.S. warships would not transit the Strait of Hormuz alongside merchant ships in a traditional escort role. Instead, the U.S. warships would be close by to assist if necessary in an accompanying role.

Defense officials told Fox News that British-flagged vessels would be accompanied as well.

‎The U.S. remains in contact with the Marshall Islands regarding the incident.

“The U.S. has full authority and responsibility for security and defense matters in or relating to the Marshall Islands, including matters relating to vessels flying their flag,” State Department spokeswoman Marie Harf said earlier this week.

 

Lucas Tomlinson is the Pentagon and State Department producer for Fox News Channel. You can follow him on Twitter: @LucasFoxNews