The operator of a U.S.-flagged cargo vessel boarded by Iranian forces as it was traversing the Strait of Hormuz says the crew is safe but that the company is still trying to determine why the ship was seized.

Cor Radings, a spokesman for Rickmers Ship Management's Singapore operations, said Wednesday the company had been in touch by phone with the crew and "they are in a relatively good condition and safe on board the ship."

There are no Americans aboard the ship.

Radings says the 24 crew is "mainly from Eastern Europe and Asia." He says there hasn't been any contact with Iranian authorities following Tuesday's seizure.

Radings says Danish shipper Maersk Line chartered the container ship and was hauling commercial goods and no "special cargo" such as military equipment.