Negotiations are under way with the abductors of the five Malaysian tugboat crew who went missing after their boat was found abandoned in the waters off Dent Haven, Tambisan near Lahad Datu on Monday.

Deputy Home Minister Nur Jazlan Mohamed said Malaysian authorities know the kidnappers and negotiations are ongoing for their release.

"Right now I ask family members of those kidnapped not to divulge any information about the communication between the authorities and the kidnappers.

"We do not want to encourage the kidnappers to continue carrying out such activities," he told reporters after the National Sovereignty Medal Presentation Ceremony to 316 members of the Sabah Prisons Department in Sandakan today.

Four of the five crew members are from Tawau and one from Felda Jengka, Pahang.

Asked whether it was necessary to provide immediate additional assets and personnel in the state's waters following the latest incident, Nur Jazlan said it was one of the steps taken by the government, but that monitoring the extensive waters off Sabah was not easy.

He said what was important was the cooperation from operators of commercial activities, who use the waters of the eastern state near the border with the neighbouring country.

He added they should notify the movement of their boats and ships to the security forces, and not use routes which carried the risk of being kidnapped.

- Bernama