DUBAI, United Arab Emirates (AP) — A ship in the Red Sea came under attack on Thursday off the coast of war-torn Yemen, a monitoring group run by the British military said.

The United Kingdom Maritime Trade Operations group said the attack happened off Hodeida, a contested port city amid that country’s yearslong civil war. It said an investigation was ongoing into the incident, without elaborating.

The US Navy’s Mideast-based 5th Fleet said it was aware of the attack, but declined to immediately comment further.

A Saudi-led coalition has been at war since March 2015 against Iranian-backed Houthi rebels who have long held the Yemeni capital of Sanaa as well as Hodeida. The Houthis, Yemen’s exiled government and the Saudi-led coalition did not immediately acknowledge the attack.

The incident marked the latest at-sea attack amid the war. In January, the Houthis seized the Emirati ship Rwabee. The Houthis described the vessel as carrying military weapons, while the Saudi-led coalition described it as carrying disassembled hospital equipment.

The ship’s Indian crew were released last month after the Houthis and the Saudi-led coalition reached a truce during the Muslim holy fasting month of Ramadan. The fragile truce is still ongoing now.