Knife-wielding pirates have been on a spree in the Singapore Strait in the last few days, with five vessels reportedly targeted since last Friday.

In one incident, six pirates boarded a tanker in the dark of night and punched an engineer and hurt the chief engineer while stealing his gold chain.

In another two incidents, the pirates confronted and tied up crew members.

The incidents, which happened in the eastbound lane of the strait, were revealed in two alerts by the Regional Cooperation Agreement on Combating Piracy and Armed Robbery against Ships in Asia's Information Sharing Centre (ReCAAP ISC).

The ReCAAP ISC was established here in 2006 as an information-sharing network between 20 nations to promote and enhance cooperation against piracy and armed robbery on ships in Asia.

In two alerts on Saturday and yesterday, it reported that three vessels were attacked last Friday, followed by two more attacks in the early hours of yesterday.

Of the three ships targeted last Friday, two were bulk carriers and one was a tanker. The two incidents yesterday involved a bulk carrier and a tanker.

According to maps provided in the alerts, the Friday incidents happened while the vessels were between Singapore and Batam, while the ships were closer to Bintan in the incidents yesterday.

The ReCAAP ISC said that due to the close proximity and short time interval between the incidents, it is possible that the same group of perpetrators was responsible.

The five incidents bring the total number of reported attacks on ships in the Singapore Strait to 29 this year, with 15 in the westbound lane of the strait and 14 in the eastbound lane.

The ReCAAP ISC advises all ships to be extra vigilant, adopt further precautionary measures and report all incidents immediately.

It also urged the relevant law enforcement agencies to step up surveillance, increase patrols and enhance cooperation and coordination so they can respond promptly to incidents.

The five reported piracy cases

THE FIVE REPORTED CASES

Dec 20, 5.30am

Jian Fa, a bulk carrier, was boarded by an unknown number of pirates. Nothing was taken from the vessel.

Dec 20, 11.25pm

Jag Lalit, a tanker, was boarded by six pirates. An engineer was punched in the face and the chief engineer suffered bruises on his neck as a gold chain was taken from him.

Dec 20, 11.40pm

The bulk carrier Akij Globe was boarded by five pirates. They entered the engine room and confronted three crew members.

They took engine and generator spares and escaped in a small boat.

Dec 23, 12.15am

Bamzi, a tanker, was boarded by three pirates who entered the engine room, where they tied up two motormen. Nothing was taken.

Dec 23, 1.55am

The bulk carrier Trust Star was boarded by six pirates who entered the engine room.

They tied up two crew members who later managed to free themselves. Nothing was taken.