TEHRAN, July 14 (Xinhua) -- Britain would facilitate a conditional release of the detained Iranian oil tanker, Britain's top diplomat said Saturday, while Iran insisted on continuing oil exports under any condition.

Britain would facilitate the release of Iran's detained Grace 1 oil tanker if Tehran promised it would not go to Syria, British Foreign Secretary Jeremy Hunt said Saturday following a phone call with Iranian Foreign Minister Mohammad Javad Zarif, amid calls for de-escalating the Gulf tensions.

"I reassured him (Zarif) our concern was destination not origin of the oil on Grace One and that UK would facilitate release if we receive guarantees that it would not be going to Syria," Hunt tweeted.

Meanwhile, Zarif stressed that Iran would continue oil exports under any circumstances and urged Britain to immediately release the oil tanker, Iranian news agency Mehr reported.

On July 4, the Gibraltar government said its law enforcement agencies and the Royal Marines had detained Grace 1 in the Strait of Gibraltar, alleging the vessel was headed to the Banyas Refinery which belongs to an entity subject to the European Union (EU) sanctions against Syria.

"Iran is neither a member of the EU or subject to any European oil embargo," Zarif said, calling the seizure "unlawful," which "sets a dangerous precedent and must end now."

On Tuesday, Mohammad Hossein Baqeri, chief of staff of the Iranian Armed Forces, said that Iran would respond to Britain's recent seizure of the Iranian oil tanker at an appropriate time and place, Tasnim news agency reported.

Earlier on Thursday, the British Ministry of Defense said that Iranian boats tried to impede the passage of a British oil tanker near the Gulf, before being driven off by a Royal Navy ship.

However, Iran denied the allegations by the British navy, saying its navy vessels carried out their regular patrolling missions in the Gulf and "there has been no encounter with foreign ships, including British ones."

On Friday, all four crew members of Grace 1, namely the vessel's captain, the chief officer and two second mates, were released on bail without charge, the Royal Gibraltar Police tweeted. "The investigation is still ongoing and the Grace 1 continues detained," it added.

In response, Iran's Foreign Ministry urged Britain to release its oil tanker "soon," saying "the British claim over the oil tanker is legally void," Iran's official IRNA news agency reported Friday.