The United Kingdom announced on Saturday that it would facilitate the release of Iran’s Grace 1 oil tanker if Tehran issues guarantees the vessel will not sail to Syria.

“Just spoke to Iranian Foreign Minister [Mohammad Javad] Zarif,” British Foreign Minister Jeremy Hunt said on Twitter. “Constructive call. I reassured him our concern was destination not origin of the oil on Grace One & that UK would facilitate release if we received guarantees that it would not be going to Syria, following due process in Gib [Gibraltar] courts.”

“Was told by FM Zarif that Iran wants to resolve issue and is not seeking to escalate,” he continued. “Also spoke to [Gibraltar’s Chief Minister] Fabian Picardo who is doing an excellent job co-ordinating issue and shares UK perspective on the way forward.”

Hunt subsequently issued a statement reiterating the United Kingdom’s interest in de-escalating tensions with Iran.

The Grace 1 was seized last week by Gibraltar authorities with the assistance of the Royal Marines on suspicion of carrying oil to Syria in contravention of E.U. sanctions. Iran condemned the move and denied the ship was heading for Syria. It threatened to capture a British vessel in retaliation.

Last week, several Iranian ships attempted to divert British oil tanker British Heritage into Iranian territorial waters. The Royal Navy frigate HMS Montrose warned them off, reportedly training its guns on the Iranian vessels and forcing them to stand off.

The Foreign Ministry announcement came after the United Kingdom declared that the navy destroyer HMS Duncan would join the Montrose in the Persian Gulf by next week to assist in protecting shipping in the area.