A vessel has been targeted off Yemen in the first attack for several weeks, its master reported. The United Kingdom Maritime Trade Operations (UKMTO) in an advisory note on Tuesday said an explosion was heard near a vessel in the Red Sea.

UKMTO has not named the vessel involved but revealed that it “received a report of an incident 120 nautical miles east of Aden, Yemen.”

The master reported a “splash and sound of explosion in the vicinity of vessel.” No casualties or damage were reported, as the incident remains under investigation.

“Vessel and crew reported safe and proceeding to next port of call,” the master added, according to UKMTO, a voluntary reporting scheme (VRS) for the Indian Ocean, specifically Red Sea, Gulf of Aden, and Arabian Sea, which details escalating tensions in the Middle East with direct impact on mariners.

UKMTO advised vessels to transit with caution and report any suspicious activity to UKMTO.

There was no immediate claim of responsibility for the blast, which UKMTO described as an “attack” on Tuesday. Authorities are investigating the incident.