Authorities in Malaysia have arrested 33 Vietnamese nationals after they were caught fishing illegally in their waters.

The Malaysian Maritime Enforcement Agency (MMEA) said they intercepted three vessels of Vietnamese origin at around 3pm on May 21, VN Express reported.

Some 30 fishermen and three boat skippers were arrested when fishing with electric pulse trawling off the coast of Sabah.

The crewmen failed to produce papers for operating in Malaysian waters. According to local media, the 33 people arrested were aged between 16 and 55.

An MMEA officer said devices for electric pulse fishing, as well as 900kg of fish in all three boats, were found. The suspects will be put on trial for violating Malaysia’s Fisheries Act.

There have been 101 cases of Vietnamese vessels allegedly trespassing and fishing in foreign waters since the beginning of last year.

Vietnam’s Directorate of Fisheries deputy head Nguyen Quang Hung said a total of 163 vessels and 1,257 fishermen had been caught red-handed.