The United Arab Emirates followed Saudi Arabia Thursday in joining a US-led force to protect Gulf shipping as tensions with Iran soared following twin attacks on key Saudi oil facilities.

The United States has pushed for the creation of the International Maritime Security Construct to safeguard trade and the flow of oil through the Strait of Hormuz.

It has so far been joined by Australia and Britain as well as Bahrain, the Gulf island state which is home to the US Fifth Fleet.

The initiative followed a number of mystery attacks on oil tankers and facilities in and around the strategic waterway through which a third of the world’s seaborne oil passes.

Tensions have risen further since Saturday when twin attacks blamed by Washington and Riyad on Tehran hit the world’s largest oil processing plant and a major oilfield in Saudi Arabia.

“The UAE’s accession to the alliance comes in support of regional and international efforts to deter threats to maritime navigation and global trade,” the director of its international security cooperation department, Salem Mohammed al-Zaabi, said in a statement.

Zaabi said the UAE joined “in order to secure the flow of energy supplies to the global economy and contribute to maintaining international peace and security.

The UAE was to host talks on Thursday with US Secretary of State Mike Pompeo who is on a Gulf tour to discuss Washington’s reponse to the strikes on Saudi Arabia’s oil industry which knocked out half its production.

Pompeo described the attacks as an “act of war”, as Riyadh unveiled new evidence it said showed the assault was “unquestionably” sponsored by Iran.

Iran has repeatedly denied it was responsible, saying that the attacks were carried out by Yemeni rebels as they themselves have claimed.

European countries have declined to join the US-led maritime force for fear of harming their efforts to rescue a landmark 2015 nuclear accord between Iran and major powers.