The kidnap-for-ransom group from the Philippines believed to be behind the abduction of two Indonesian fishermen two weeks ago have demanded a ransom of RM4 million for their release.
Sabah Police Commissioner Datuk Omar Mammah said the family of one of the victims received a call from one of the captors at about 10.24am on Sept 18, to arrange for payment in order to secure their freedom.
"The wife of one of the victims, who is in Sulawesi, Indonesia, received the call from the Philippines.
"No deadline has been set so far (for the payment).
Omar said police had received plenty of reliable information from fishermen who had seen pump boats believed to belong to the suspects, who were still at large.
"We are intensifying security efforts from north of Kudat to south of Tawau. So far the suspects have not issued any threats," he added.
Omar said police were studying the feasibility of lifting the ban on pump boats as suggested by the new Parti Warisan Sabah-led state government a few months ago.
He said fishermen still used the pump boats along the coastline, but not in the open seas.
"We are still waiting for the decision from the government. We will see what justifications are given for the use of pump boats. If the government continues banning the use of these vehicles, we will follow their decision and enforce the law," he said.
Pump boats are small craft with converted or recycled motorbike or car engines that are much cheaper than "proper" outboard boat motors.
They are popular in the seas between Sabah and southern Philippines and are normally used by small-scale fishermen and by shady characters.
Pump boats were banned several years ago following a series of cross-border crimes on the east coast of Sabah, especially kidnappings. This part of the maritime border with the Philippines is only an hour away by boat from the mainland.
The town of Semporna in eastern Sabah is seen as the gateway for cross-border travel, especially to the troubled chain of Sulu islands in the Phillippines.
A few months ago, the state government announced that it might lift the ban to help poor fishermen.
In the latest kidnapping incident, Indonesian fishermen were abducted by armed kidnappers off the coast of Semporna during curfew hours at about 1am on Sept 11.
They were on a fishing vessel and had just docked at the Pulau Gaya when one of the crewmen heard the engine of an approaching pump boat. Suddenly, the power supply at their vessel was cut off.