Pirates hijack one small coastal tanker every two weeks on an average in the waters off Southeast Asia, a leading piracy watchdog said on Tuesday as it expressed concern over the growing menace.
Southeast Asia accounts for 55 per cent of the world's 54 piracy and armed robbery incidents since the start of 2015, Pottengal Mukundan, Director International Maritime Bureau (IMB) said in a statement.
"The frequency of these hijackings is occurring at least every two weeks in Southeast Asia which is an increasing cause for concern. There's a risk that the attacks and violence could increase if left unabated," said Mukundan.
"A number of these incidents have occurred in international waters, and a robust and coordinated regional response is required in order to counter these threats," it added. The IMB has been monitoring world piracy since 1991.
After a steady drop in global piracy over the last few years, attacks rose 10 per cent in the first quarter of 2015 on the same period of 2014.
Worldwide, pirates took 140 hostages in the first three months of 2015, three times as many as during the same period in 2014.
A total of 13 seafarers were assaulted and three injured, the statement said.
IMB has recorded 23 ship hijackings in Southeast Asia since April 2014, with six in the last three months.
Most are carried out by armed gangs targeting small coastal tankers to steal their cargoes of fuel.
The country with the highest number of attacks is Indonesia, accounting for almost 40 per cent of 2015 attacks, with two vessels hijacked and 19 vessels boarded.