The captain of a supertanker carrying Iranian oil held off Gibraltar has told the BBC the force Royal Marines used to seize it was "unnecessary".
The Grace 1 was detained earlier this month after marines were helicoptered on board.
The Indian national who was arrested and bailed by Gibraltar authorities said his crew has been caught up in a "political game".
He added that he "wasn't aware" the ship was doing anything wrong.
Gibraltar says the evidence it has contradicts the statements made by the captain and that it detained the ship for attempting to breach EU sanctions on oil sales to Syria.
Police in Gibraltar said minimum force was used.
Speaking to the BBC, the captain said the police made a radio request to board his tanker and a ladder was being lowered to them - but then a military helicopter started descending.
He said marines "came up to the bridge and just pointed the gun" at them and made them kneel.
The seizure sparked a rise in tensions between the UK and Iran.
The Royal Navy's HMS Duncan has now arrived in the Gulf to protect British-flagged ships travelling through the Strait of Hormuz.
The Type 45 destroyer will work alongside HMS Montrose until she docks for routine maintenance in late August.
Following the action taken by the marines, Iran has captured a British flagged oil tanker, the Stena Impero, in the strategic Strait of Hormuz "for failing to respect international maritime rules".
But Iran's Guardian Council said the seizure was in response to Britain's role in capturing their oil tanker.