Thirty-four illegal immigrants believed to have made their way to Hong Kong from Vietnam in two ricketty wooden boats were rounded up by police just after they landed yesterday. The migrants, some of whom were armed with knives, are believed to have paid snakeheads US$80 (HK$622) to US$100 for the treacherous journey and are the latest in a series to arrive in Hong Kong from Vietnam this year. The men, aged between 19 and 51, are believed to have travelled almost 1,000km in ramshackle open boats, one of which has been recovered by police. They were arrested separately in small groups in Tuen Mun, Castle Peak and Tsuen Wan after landing in Lung Kwu Tan on the western-most coast of the New Territories, at about 3am yesterday. An extensive hunt involving 100 officers from the Marine Police and Castle Peak division was mounted in the early hours after a taxi driver raised the alarm. The driver had received a radio order to pick up passengers in Pillar Point, but he did not stop after driving past and seeing them because he suspected they were illegal immigrants. Police later intercepted and arrested 25 of the Vietnamese on Lung Mun Road as they walked towards Tuen Mun city centre, where a roadblock had been set up. A further six Vietnamese were arrested on a minibus heading to Tsuen Wan along Castle Peak Road, two more on Golden Beach after they attempted to steal swimmers' property and another after he tried to rob a taxi driver at knifepoint. Last night it was believed at least one more Vietnamese man was still at large. Police seized home-made weapons and knives from 11 of the group. Some of the blades were 60cm long. Preliminary investigations indicated that at least 35 men left the northern coastal city of Haiphong in Vietnam on June 30. The arrested men were last night being detained at Tsuen Wan and Castle Peak police stations. Lung Kwu Tan is a black spot for illegal immigrant landings. A police constable shot and wounded a 21-year-old Vietnamese man who approached him wielding a knife in the area on May 22. Nine other Vietnamese were also intercepted. They were among a group of about 20 who landed in Lung Kwu Tan after being told by snakeheads that there was a strong demand for workers for the Disneyland project. Police have arrested 80 Vietnamese illegal immigrants so far this year, compared to 170 for the whole of last year.