The NATO military alliance and the European Union on Tuesday joined a growing chorus of international condemnation of Iran’s alleged attack on a merchant ship in the Arabian Sea last week and urged Tehran to respect its international obligations.

Last Thursday’s drone strike on the MV Mercer Street killed a British national and a Romanian. It was the first known fatal strike on commercial shipping in the region after years of tensions over the tattered nuclear deal between western nations and Iran.

NATO spokesman Dylan White said the 30-nation alliance joins members the U.S., U.K. and Romania “in strongly condemning the recent fatal attack on the MV Mercer Street off the coast of Oman, and express our condolences to Romania and the United Kingdom for the losses they have suffered.”

“Freedom of navigation is vital for all NATO allies, and must be upheld in accordance with international law,” White said. “Allies remain concerned by Iran’s destabilizing actions in the region, and call on Tehran to respect its international obligations.”

The U.S.-led military alliance plays no role in the region or in the Iran nuclear agreement, although some of its member countries do.

The EU, meanwhile, deplored the attack, expressed its condolences for the victims and called for a thorough independent investigation.

“Such acts contrary to the security and freedom of navigation in the region are unacceptable,” European Commission spokeswoman Nabila Massrali said. “All parties concerned must avoid all actions that could undermine peace and regional stability.”

(AP)