The victims were a 47-year-old man from Jalan Tekam here and a 21-year-old man from Song, Kapit.
The attack occurred when they were having some drinks with a girlfriend, said to be a Chinese national, on the sidewalk of the café.
The assailant, who was wearing a helmet and clad in a red jacket, approached the three, whipped a gun and fired several shots at the victims from a distance of about five metres.
The man, who then fled on a motorcycle parked nearby, was believed to have used a pistol, based on the casings found at the scene.
In confirming the incident, Sarawak police commissioner Amer Awal said a special task force had been formed to investigate the killing.
“It is too early for us to reveal further developments in the case at the moment,” he said in a statement.
Amer asked members of the public not to speculate on the case and let police investigate it thoroughly.