The Serudong river is three miles within and runs parallel to the International border in the south of Tawau Residency of Sabah. At the mouth of the river is the village of Serudong. The village itself is about four miles from the border. Across the border lies the Indonesian island of Nunukan, where there are located two Indonesian marine platoon bases. These Indonesian marine forces ostensibly carrying out anti-smuggling activities in East Kalimantan, are known to have lately organised training camps for training Indonesian Irregulars, who made incursions into Tawau Residency in mid-December, 1963.

Security Forces in Tawau Residency are continuing with “mop-up” operations after the Kalabakan raid of 29 December, 1963, by Indonesian Regulars and Irregulars totalling between 140 and 180 men of whom about 31 were lndonesian marines. This force was made up of small groups of 30-40 men each. Security Forces in the Serudong area of Tawau Residency received information that a small enemy group was operating in this area.

On 16 January a patrol of Security Forces met with this enemy group. The group were identified as enemy by the uniforms they wore and because they were armed with an assortment of weapons not used by Malaysian forces, Fire was immediately exchanged by both sides. During the fire fight one enemy was killed, and the enemy disengaged and withdrew in a southerly direction. There were no Security Force casualties. From interrogation of previous captured and surrendered enemy personnel and enemy documents recovered in earlier incidents, this dead enemy has been identified as Berunton alias Ramli, who was an Indonesian Marine corporal of the Korps Komando Operasi. Berunton was also a leader of one of the enemy groups which incurred into the Kalabakan area.

At the time of contact, this enemy group appeared to have been lost in the Serudong area and without food for several days. It was apparently trying to withdraw to Indonesian Kalimantan. Subsequently on the 19 January at 1630 hours two more enemy surrendered to a Security Force patrol in this same area. This was the result of Security Forces follow-up after the incident on 16 January. These two enemy were armed and in uniform and on sight of the Security Force patrol came out and surrendered, These two enemy were immediately sent to Tawau for interrogation by the police and army, and it was discovered from their statements that they were in the same group that was contacted on 16 January 1964.