TEL AVIV, Israel (AP) — Drones attacked a vessel carrying aid to Gaza on Friday in international waters off Malta, the group organizing the shipment said. A fire broke out but was brought under control, according to authorities.

A nearby tugboat responded to a distress call from the Conscience, which was carrying 12 crew members and four civilians, Malta’s government said, adding that those aboard refused to leave the ship. The group was safe and no injuries were reported, it said.

The Freedom Flotilla Coalition accused Israel of attacking its ship. The group did not provide evidence for that claim or to show that the fire was caused by drones, but in a video it shared an explosion could be heard. Another video showed a fire blazing.

The Israeli army did not respond to a request for comment.

Israel has cut off Gaza from all imports, including food and medicine, since the beginning of March, leading to what is believed to be the worst humanitarian crisis in nearly 19 months of war with Hamas.