Speaking on Friday on the release of Grace 1, which Gibraltar police and British Royal Forces seized in early July but was released yesterday, Mousavi said the release of the vessel was a matter of law and had nothing to do with any third party.

Mousavi added that Iran will continue to sell its oil to any of its new and old customers.

He also said that Iran will continue to support Syria in all fields including energy and oil.

The spokesman also noted that Grace 1 was not sailing towards Syria, as Iran insisted from the start of the subject, adding that even if the destination of the oil tanker had been Syria, it would have been nobody's business and would have made no difference to Iran.

Mousavi further noted that the other side brought up the issue of commitment in a bid to save face in getting rid of their illegal action and act of piracy.

Late on Thursday, Iranian Foreign Minister Mohammad Javad Zarif provided a copy of Iran's embassy note to UK’s Foreign and Commonwealth Office, and reiterated that London’s detention of a supertanker carrying his country’s oil was totally illegal from the very beginning.

Iranian Foreign Minister Mohammad Javad Zarif in a message referred to Iran's embassy note to UKFCO, saying seizure of tanker carrying Iran oil was 100 percent unlawful.

"Our London Embassy note to UKFCO protested the illegal detention of Grace1; Repeated public statements about destination; and made it crystal clear that the European Union’s sanctions do not apply to Iran—a position shared by most Europeans," Zarif tweeted on Thursday.

"Nothing changes the fact: detention was 100% unlawful," he underlined.

Authorities in Gibraltar finally released the Iranian oil tanker on Thursday, ignoring the US request to detain the vessel for a further period.

Following the decision by the Gibraltar court, Iran’s Ambassador to the UK Hamid Baeidinejad also said the US effort to press the government of Gibraltar to transfer control of the vessel to Washington had failed.

“The US, with its desperate, last-minute efforts, intended to prevent the release of the [Grace 1] oil tanker from detention, and was faced with humiliation,” Baeidinejad added.

The envoy stated that all preliminary steps have been taken to ensure the tanker’s movement toward free waters and “the vessel will soon leave the Gibraltar region”.

In early July, British marines and Gibraltar police seized the Iranian tanker off the Southern coast of the Iberian Peninsula, claiming that the ship was transporting crude oil to Syria “in violation” of the EU sanctions placed on Damascus. Washington had applauded the move, hailing it as a sign that Europe is on board with the US unilateral sanctions against Tehran.

Iran had condemned the “illegal move” of London and described it as “tantamount to piracy”. Tehran accused the UK of doing Washington’s bidding and helping the US attempt to stifle the Islamic Republic’s oil exports, rejecting London's claim that the supertanker was carrying crude for Syria.