A crew member has been hospitalised in a brutal attack by suspected robbers on a Singapore-flagged tanker off Indonesia.

Maritime intelligence company Ambrey Analytics said the unnamed vessel was boarded by two armed individuals as it was transiting eastbound through the Phillip Channel in the Singapore Strait, 4.3 nautical miles (8 km) north-west of Kapalajernih Island on Tuesday evening.

The suspects were armed with bladed weapons and were initially detected on the stern poop deck.

After the attack, the ship headed to the Eastern Petroleum A Anchorage in Singapore, where on Wednesday it was carrying out a ship-to-ship transfer of its cargo.

Authorities there later revealed that one seafarer was “stabbed multiple times” during the incident, Ambrey added.

The two raiders subsequently escaped.

The crew member was taken to hospital, where they were receiving medical attention.

There was no information about the seafarer’s condition.

No items were reported stolen, Ambrey said.

During the incident, the tanker was underway at 8.5 knots, with an estimated freeboard of 8.7 metres.

Ambrey observed the ship arriving at the Singapore anchorage three hours after the attack.

No damage has been reported to the vessel.

Ambrey advised that vessels transiting the Singapore Strait with freeboards of less than 10 metres are at “heightened risk” of such raids.

“Crews should lock down access to the accommodation block and ship’s stores,” the company said.

“It is recommended to carry out partnered deck patrols. Do not confront criminals,” Ambrey added.