LONDON: The Indian captain of an Iranian ship that was seized by Royal Marines earlier this month has said that the British soldiers used "brute force" when they detained his ship, according to a media report on Tuesday.

The Grace 1 tanker was detained by Gibraltar authorities with the help of Royal Marines on July 4 on the suspicion that it was ferrying a cargo of more than 2 million barrels of crude oil to Syria in breach of the European Union sanctions.

The master and chief officer of the ship - both Indian nationals - were held in relation to breaches of the European Union Regulations 36/2012, concerning restrictive measures in view of the situation in Syria.

They were later granted "police bail with conditions".

The captain, an Indian national who asked not to be named, told the BBC that British soldiers forced his unarmed crew to kneel on the deck at gunpoint after landing on the ship in a helicopter.

He said he was radioed a police request to board his ship and lowered his ladder. But before anyone could board, a military helicopter landed on the ship in a "very dangerous" move.

He told the BBC that he identified himself as the captain but the marines ignored him and instead pointed their guns and shouted "look forward, look forward".

"There was no regulations… we had 28 unarmed crew. I was in a state of shock, everybody was in a state of shock," he was quoted as saying.

"How do you come on a ship like this with armed forces and such brute force. For what reason?" he said.

The captain said the marines could have boarded the ship and simply told him he had been arrested.

He told the BBC that he and his crew had been advised by the Indian High Commission officials to remain anonymous while legal proceedings are on-going.

Asked whether he felt there was anything illegitimate about his ship or the cargo, he said he had "followed company procedures" and he did not know about the EU sanctions against Syria.

The Ministry of Defence (MoD) said the seizure complied with "international rules and norms".

It said the operation on Grace 1 was a "standard boarding" and that British armed forces were "held to the highest standards of professionalism".

Royal Gibraltar Police said the marines had acted in support of its officers and applied "the minimum use of force" to ensure officers could get on board, deal with the crew and take control of the vessel. It added that the ship's four senior officers had been interviewed under caution.

The Gibraltar government said it had evidence which contradicted statements made by the captain and would release its own statement soon.

The seizure of the oil tanker sparked a diplomatic crisis between the UK and Iran , which has escalated since then.

Iran blames the US for arranging to have its ship seized in the wake of sanctions imposed against Tehran with the aim of halting all its oil exports. European countries do not have sanctions against Iran but have had them in place against Iran's ally Syria since 2011.

