TASS, July 8. Gibraltar (British overseas territory on the Pyrenean coast) authorities’ seizure of the Grace 1 tanker is an "act of piracy", Iranian Foreign Ministry Spokesman Abbas Mousavi said on Monday.

"The seizure of the tanker is an act of piracy. Tehran strongly rejects such actions which lead to increasing tensions in the region," Al Jazeera TV channel quotes him as saying. He also pointed out that the oil tanker did not enter territorial waters of any states. Mousavi stressed that Iran was continuing to take actions aimed at the release of the ship and was in constant contact with European diplomats.

"We demand that London release the oil vessel as soon as possible," he reiterated.

The Panama-registered Grace 1 supertanker was detained by Gibraltar on July 4 on suspicion that it was transporting crude oil to Syria in violation of the sanctions. The UK Royal Marines took part in the operation. According to Gibraltar authorities, the 28 crewmembers, citizens of India, Pakistan and Ukraine, were aboard the tanker. In response, the Iranian Foreign Ministry summoned British ambassador in Teheran. Acting Spanish Foreign Minister Josep Borell said that the operation was conducted at the US request.