The government of Gibraltar thanked British forces for seizing an oil tanker bound for Syria on Thursday.

British Royal Marines and port officials of Gibraltar boarded an oil tanker believed to be bound for Syria carrying Iranian crude oil.

Authorities said that the Marines had a reason to believe the ship, called the Grace1, was carrying crude oil to the Banyas Refinery station in Syria. The refinery is subject to European Union sanctions that are part of a larger group of sanctions imposed on Syria.

Gibraltar is a British Overseas Territory of less than three square miles on the tip of the southern Iberian peninsula, bordered by Spain to the north and primarily dominated by the Rock of Gibraltar.

The BBC reported that 30 marines, from 42 Commando, flew from the U.K. to Gibraltar to help seize the tanker, at the request of the Gibraltar government.

‘Firm Action’ Commended

Fabian Picardo, Gibraltar’s chief minister, praised the Marines for boarding the Syria-bound oil tanker. He called the capture necessary and said it ensures the commitment of Gibraltar to international regulations and legal order.

Picardo thanked the police, custom and port authorities for collaboration on the detention of the ship.

The BBC quoted Picardo as stating that he sent letters to the presidents of the European Union Commission and the European Council keeping them updated about the incident. He stated that the government’s actions were based on the terms of E.U.-enforced Syrian sanctions.

A spokesman for Prime Minister Theresa May said that the P.M. welcomed the “firm action” by the Gibraltar authorities, the BBC reported.

The Refinery facility of Banyas is located in the Syrian Mediterranean town of Tartous and is considered a subsidiary of the General Cooperation for Refining and Distribution of Petroleum Products. The refinery belongs to the Syrian Ministry of petroleum.

EU-Imposed Syrian Sanctions

The E.U.-imposed sanctions on Syria include an embargo on oil imports, limited investment across Syria, as well as the freezing of Syrian funds and assets of the Syrian Central Bank located in European Union countries.

An embargo has also been placed on imports of equipment and machinery that could be used in the repression of civilians.

Last June, the U.S. imposed a new set of sanctions on sixteen dignitaries and entities that are suspected to be relevant to the current Syrian crisis.

Syrian Civil War

Since 2014, the E.U. has imposed sanctions on the Syrian refinery as part of the E.U.’s response to Syria’s civil war which began in 2011.

According to the E.U., the oil production plant supports the Syrian regime of Bashar Alasad which the E.U. says has been engaged in the repression of Syrian civilians.

Since 2011, the Arab Republic of Syria, home to nearly 19 million residents, has endured a civil war sparked by mass protests demanding social and economic reforms.

Since then, hundreds of thousands have been killed and injured, while millions more have been displaced. In recent years, Russia became a key ally for the Syrian regime intervening in the war and helping Syria defeat the armed opposition groups.