CHINESE patrol boats waiting just outside Hongkong waters last night pounced on three Vietnamese ships trying to sail from Hongkong in convoy in a vain bid for protection. Last brief radio messages from the Vien Dien, Phu Ninh and Song Cam 04, received by the Marine Department's Vessel Traffic Centre suggested the small coastal freighters had been seized. Reports described patrol boats chasing the ships to within four nautical miles of Po Toi Island at about 6 pm, with armed officers boarding at least two of the ships. No reports of injuries have been received. It is believed all three left Yau Ma Tei legally, with port clearance and full cargo manifests detailing goods, including second-hand cars and electrical appliances. The news is being seen as further evidence of the strength of China's shipping intelligence network within Hongkong, with the Public Security Bureau knowing the exact movements of targeted ships. The ships appear to be the latest victims of official Chinese anti-smuggling crackdowns against trade from Hongkong to Vietnam, involving mainly Vietnamese companies and Vietnamese flagged ships. Earlier raids last spring resulted in unsuccessful British and Hongkong demands for clarification, raised in London and Beijing. Twelve ships are currently under detention in high security at a Chinese military base in Yantian Harbour on the Guangdong coast, some of the 18 seized so far this year after legally leaving Hongkong.