18 Indians aboard British-flagged oil tanker seized by Iran
The company also said that the vessel is no longer under the control of the crew and remain uncontactable, reported CNN.
The Stena Impero was seized on Friday by the Iranian Revolutionary Guard.
Iran's seizure of a British-flagged oil tanker was allegedly due to a collision with an Iranian fishing boat, Iran's official news agency IRNA said.
Stena Bulk, a Swedish company which owns the vessel, said they have been unable to contact the ship, which was seized in the Strait of Hormuz, a key waterway in the region.
"There are 18 Indian and five crew members from Russia, Philipines, Latvia and other countries on board of Stena Impero. The captain is Indian, but the tanker is UK-flagged," the news agency quoted Allahmorad Afifipour, director general of Ports and Maritime Affairs of Hormuzgan province, as saying.
"Stena Impero crashed into a fishing vessel," he said, adding that the captain of the vessel tried to make contact with the UK tanker, but there was no signal.
"Soon after the vessel was approached by unidentified small naval craft and a helicopter during her transit of the Strait of Hormuz in international waters...the vessel suddenly deviated from her passage to Jubail and headed north towards Iran," the company which owns the tanker said in statement.
The vessel was in full compliance with all navigation and international regulations, it said.
Erik Hanell, President and Chief Executive, Stena Bulk, said: "There are 23 seafarers onboard of Indian, Russian, Latvian and Filipino nationality. There have been no reported injuries and the safety and welfare of our crew remains our primary focus.
"We are in close contact with both the UK and Swedish government authorities to resolve this situation and we are liaising closely with our seafarers' families," Hanell said.
In early July, British marines and Gibraltar police seized an Iranian tanker off the Southern coast of the Iberian Peninsula.
Gibraltar claimed that the ship was transporting crude oil to Syria "in violation" of the EU sanctions placed on Damascus, escalating tensions in the Gulf.