The Malaysian Maritime Enforcement Agency (MMEA) warned that the gunmen have become cleverer and more cautious in recent months.
They are picking targets more carefully due to increased patrols from authorities, the Star daily reported.
The MMEA said the tactic first came to light at the end of last year when eight men were caught in waters off Pengerang.
MMEA southern region enforcement chief Adon Shalan said gangs were using ferry boats and water taxis to ply the route between Batam and Malaysia or Singapore.
"Once
