Updated at 3.15pm:
Eight female illegal immigrants were arrested in Tseung Kwan O following the detention of two suspected snakeheads off Sai Kung in the early hours of Wednesday morning.
At about 2am, the radar of a police launch showed an unlit vessel moving at high speed from Clear Water Bay.
Orders to stop were ignored and the Marine Police gave chase.
The four-metre long sampan with two mainlanders on board was intercepted after a short while about 2.5 nautical miles east of the Ninepin Group of islands off Sai Kung.
The two mainlanders, aged 25 and 35, were allegedly on their way back to the mainland after conveying some illegal immigrants to Hong Kong.
Police later found the eight illegal immigrants, aged between 18 and 22, in Po Toi O Village.
Police are looking into the route that the two mainlanders took and investigating if the young women arrested had any connection with the suspected snakeheads and the purpose of their entry to the territory.