A suspected drone attack on a merchant vessel with 21 Indian crew in the Arabian Sea off India's west coast caused an explosion on Saturday but there was no report of any casualties in the incident, according to military sources and a maritime agency.

A P-8I maritime patrol aircraft, deployed by the Indian Navy after the United Kingdom Maritime Trade Operations, or UKMTO, reported the incident, ascertained the safety of the vessel and its crew, Indian military sources said.

An attack by Uncrewed Aerial System (UAS) on a vessel 200 nautical miles South West of Veraval, India, caused "an explosion and fire", the UKMTO said on its website.

Indian Navy officials said a maritime patrol aircraft sent to the area flew overhead the merchant vessel and established contact with it.

"The aircraft ascertained the safety of the vessel and its crew," said a Navy official.

The Navy has already dispatched a frontline warship for safety of the cargo vessel.

It is learnt that the Indian Coast Guard diverted its ship ICGS Vikram to the area where the merchant ship is located.

The military sources said the vessel now heading towards the nearest port.

The vessel was reportedly bringing crude oil from a port in Saudi Arabia to Mangalore port.

They said out of 22 crew members onboard the vessel, 21 are Indians.

In a brief statement, the UKMTO said it "received a report of an attack by Uncrewed Aerial System (UAS) on a vessel causing an explosion and fire. Incident 200 NM South West of Veraval, India." It said the fire was "extinguished" and there were no casualties. "Authorities are investigating.

Vessels are advised to transit with caution and report any suspicious activity to UKMTO," it said. PTI MPB.

(Except for the headline, this story, from a syndicated feed, has not been edited by staff)