Sungei Pinayas is a small river lying approximately six kilometres south of Kalabakan running from west to cast/into Cowie Harbour in Tawau Residency in Sabah. It lies about ten kilometres north of the Indonesian border. This area is covered by thick jungle and vast areas of swamp. On the 28 January a Security Force patrol of about thirty strong were operating in the area of Sungei Pinayas looking for enemy tracks or resting places along the river bank when they were suddenly encountered by an enemy party, who were armed and uniformed. Fire was exchanged by both sides which resulted in three enemy being killed with no casualties to Security Forces. On breaking contact the enemy withdrew southwards. The following arms and ammunition were also recovered from this contact : One sten gun, two rifles Mark 4, five hand-grenades. four sten magazines, 134 rounds of 9 mm. ammunition, 276 rounds of .303 ammunition.
30 January, 1964
Enemy Activity in the Umas-Umas Area. The Umas-Umas river runs from north to south parallel to the Merutai river about six kilometres west of Merutai. At about 1100 hours on 30 January a Security Force patrol operating in the Umas-Umas area made contact with an enemy party. Fire was exchanged and one enemy was killed and another captured while one soldier of the Security Forces was slightly wounded. The killed and captured enemy have been identified as lndonesian irregulars.
1 February, 1964
Enemy Activity in the Tawau Area. On 1 February, 1964 about 1845 hours, acting on information, a Special Branch team from Tawau took possession of a quantity of explosive in Tawau harbour which had been brought to Tawau by boat on the same day, by an agent of the Korps Kommando Operasi based in Tarakan. This agent had been trained in the use of explosives in Tarakan last month. On his arrival this agent was found to be in possession of the following in his boat which were seized:
1. TNT (6 kilos in weight).
2. Five detonators contained in five empty cartridges.
3. About three/yards of cortex.
4. About two yards of fuse.
5. Half a box of matches with a new razor blade in the match box.
6. Three Russian FI hand grenades.
7. A bundle of anti-Malaysia pamphlets.
The TNT packed with cortex and was ready for instant use. The nature of the packing of the TNT showed it had been done by an expert. Under interrogation this agent has stated that his order of tasks of priority in Tawau was as follows:
(a) Power station.
(b) Water-pump station.
(c) Fuel dumps.
He had also been instructed to throw hand-grenades into any crowded place.