THE waters off Indonesia's Pulau Nipah, some 10km south of Tuas and north-west of Batam, have seen a spike in attacks on ships, prompting maritime watchdogs to warn vessels to be extra vigilant when anchored in the area.
The Singapore-based information sharing centre of the Regional Cooperation Agreement on Combating Piracy and Armed Robbery against Ships in Asia (ReCAAP), in its latest report out this month, highlighted seven incidents involving tankers anchored at Nipah Anchorage in the first nine months of this year.
Earlier this month, another four attacks took place on ships anchored at Nipah and nearby Karimun Anchorage, the International Maritime Bureau (IMB) said.
All but one occurred between 2am and 5.30am and involved groups of four to six robbers.
There has been a steep decline in piracy and armed robbery on ships passing through the Strait of Malacca and Strait of Singapore in recent years, partly as a result of coordinated patrols by littoral states.
But these latest robberies have sparked concern that pirates are resurfacing in waters off Indonesia and could pose a greater threat if not checked.
"These attacks are not like those off Somalia, they are more low-level and localised," said Mr Noel Choong, head of IMB's piracy reporting centre in Kuala Lumpur.
"But for a seafarer, it does not matter what a pirate is looking for as the seafarer may be injured or killed," he noted.
"If the police and navy can concentrate efforts on these few areas, it will bring down the attacks."
ReCAAP recorded 55 attacks in Indonesian waters over the first nine months of this year, up from 48 over the same period last year and 11 in 2009.
In most cases, the robbers were armed with knives and weapons like machetes and metal rods. They made off with engine spare parts and bearing shells.
IMB has recorded 12 more attacks this month, the latest on a chemical tanker at Belawan anchorage, another hot spot off North Sumatra, on Sunday.
Dr Sam Bateman, senior research fellow at the S. Rajaratnam School of International Studies' Maritime Security Programme, said security in some Indonesian ports and anchorages is a problem.
He suggested better coordination between agencies providing security, more active patrolling and enhanced radar coverage.
Commodore Agus Heryana, commander of the Indonesian Navy base at Tanjung Pinang on Bintan, said crew should also play a part and stay vigilant.
"(The robbers) usually strike before dawn, when patrol boats rarely pass," he said.
"We will act if we encounter them."