Britain’s seizure of an Iranian oil tanker off Gibraltar last week will not be “unanswered”, Iran’s armed forces chief of staff, Major General Mohammad Bagheri, said on Tuesday, according to the semi-official Tasnim news agency.

“Capture of the Iranian oil tanker based on fabricated excuses … will not be unanswered and when necessary Tehran will give appropriate answer,” Bagheri said.

British Royal Marines boarded the ship, Grace 1, off the coast of Gibraltar on Thursday and seized it over accusations it was breaking sanctions by taking oil to Syria.

Iran has demanded the immediate release of the oil tanker, while an Iranian Revolutionary Guards commander threatened on Friday to seize a British ship in retaliation.

According to the British Ministry of Defense, the Iranian vessel was seized at the request of their U.S. partners. Shortly after its seizure, U.S. National Security Adviser John Bolton applauded the British Royal Marines for this move.

On Friday, an Iranian general warned the country could seize a British ship in retaliation.

“If Britain does not release the Iranian oil tanker, it is the authorities’ duty to seize a British oil tanker,” Mohsen Rezai, a Major General in the Revolutionary Guards Corps and head of the country’s influential Expediency Council, which advises the Supreme Leader Ayatollah Ali Khamenei.

“Islamic Iran in its 40-year history has never initiated hostilities in any battles but has also never hesitated in responding to bullies,” Maj Gen Rezai added. (NAN)