The operator of a Marshall Islands-flagged cargo vessel boarded by Iranian forces as it was traversing the Strait of Hormuz said Wednesday it has confirmed the crew is safe but that the company is still trying to determine why the ship was seized the previous day by the Islamic Republic.

The MV Maersk Tigris was taken Wednesday to Bandar Abbas, the main port for Iran’s navy, under escort by Iranian patrol boats, according to Maersk Line, the company that had chartered it. Tehran has not offered any clarification on the incident, which comes at a critical time during Iran’s relations with the United States and the West amid talks about its contested nuclear program.

Cor Radings, a spokesman for the ship’s operator, Rickmers Ship Management in Singapore, which is part of a Hamburg-based shipping group, said the company had been in touch by phone with the crew earlier in the day.

“We have had the confirmation that they are in relatively good condition and safe on board the ship,” he said.

Iranian forces remain on board the ship, Radings said, adding there has been no contact yet with Iranian authorities.

Iranian forces boarded the MV Maersk Tigris on Tuesday after firing warning shots across the bridge, prompting the U.S. Navy to dispatch a destroyer and a plane to the area in response.

Radings confirmed reports that there were no Americans on board, identifying the 24 people crew members as “mainly from Eastern Europe and Asia.” Iranian state television on Tuesday said the crew members were from Britain, Bulgaria, Romania and Myanmar. Romania’s Foreign Ministry confirmed four of the sailors were its citizens, declining to elaborate due to privacy laws.

Iran’s semi-official Fars news agency quoted the maritime deputy director of Iran’s Ports and Sailing Organization, Hadi Haghshenas, as saying the seized ship was still under arrest Wednesday.

“A Maersk Line cargo ship seized in the Strait of Hormuz by the Islamic Republic was because of some unpaid debt,” Fars quoted Haghshenas as saying. “Maersk Line owes some money to an Iranian company and the court has ruled that Maersk should pay the debt.”

The report did not elaborate. Michael Storgaard, a spokesman for Danish shipper Maersk Line, earlier said his company had not been “able at this point to establish or confirm the reason behind the seizure.”

U.S. firm Oaktree Capital, a global investment firm based in Los Angeles, would not confirm a shipping industry magazine’s report that it owned the MV Maersk Tigris and referred any questions to Radings. Radings would only say the ship was owned by “private investors” and would not elaborate.

Maersk chartered the container ship and was hauling commercial goods and had no “special cargo” such as military equipment, said Radings, speaking by phone from Spain.

The U.S., other world powers and Iran are trying to hammer out a final deal over Iran’s nuclear program. Last week, the U.S. Navy dispatched an aircraft carrier and guided missile cruiser to the Arabian Sea amid worries that a convoy of Iranian cargo ships was headed to Yemen to deliver arms to the Shiite rebels fighting to take over Yemen.

In Tuesday’s incident, the intercepted ship was traveling through the narrow Strait, which is technically Iranian and Omani territorial waters, but under international agreement is open to foreign ships making an innocent passage, according to the Pentagon.

The Strait of Hormuz is the route for about a fifth of the world’s oil and is only about 33 kilometers (21 miles) wide at its narrowest point. Ships traversing the chokepoint have even less room to maneuver. The shipping lane in either direction is only 2 miles wide, with a 2-mile buffer zone between them.

U.S. Navy officials said Tuesday that several Iranian Revolutionary Guard Navy vessels had surrounded a U.S.-flagged cargo ship, the Maersk Kensington, last Friday as it was transiting the Strait of Hormuz. No shots were fired, the Iranian vessels broke off contact, allowing the cargo ship proceeded without further incident, they said.

(AP)