Iran’s top military commander warns that Britain’s illegal seizure of an Iranian oil tanker in the Strait of Gibraltar will not go “unanswered.”

“The capture of the Iranian oil tanker will not go unanswered and Tehran will give a response to [the UK’s] contemptible move at an appropriate time and place when necessary,” Chairman of the Chiefs of Staff of the Iranian Armed Forces Major General Mohammad Baqeri said on Tuesday.

Gibraltar police and customs agencies, aided by a detachment of British Royal Marines, boarded and impounded Iranian supertanker Grace 1 in the Strait of Gibraltar last week, upon a request from the United States.

Iran’s Foreign Ministry summoned Britain’s ambassador to the country to express its strong protest at the move.

At the Foreign Ministry, Rob Macaire was told that the British Royal Marines’ move was tantamount to “maritime piracy”, and that the UK must immediately release the oil tanker.

It was also emphasized that the Islamic Republic of Iran will employ all its political and legal capacities to secure the release of the vessel and uphold its rights.

Spain, which challenges the British ownership of Gibraltar, said the action was prompted by a US request to Britain and appeared to have taken place in Spanish waters.

Experts believe the measure taken by the British government in seizing the Iranian tanker is illegal and can have serious consequences for the government in London.

Mohsen Rezaei, the secretary of Iran’s Expediency Council, has called for the seizure of a British oil tanker in case London refuses to release the Iranian vessel.

Elsewhere in his Tuesday remarks, Baqeri hailed the Iranian Armed Forces for shooting down an intruding US spy drone in the Persian Gulf last month, saying the move proved Iran’s growing military power.

“Today, the Islamic Republic of Iran enjoys the necessary power in the missile, naval and air defense areas and this fact has posed a serious challenge to one of the enemy’s points of strength, namely its aerial and missile capability,” he said.

The drone that Iran shot down was targeted with Iran’s indigenous Khordad 3 air defense system. Its operators received warnings by the IRGC to leave Iranian airspace before it was shot down.