Six days before a fireworks ceremony to mark completion of civil work on the Tsing Ma Bridge, Highways Department chiefs warned yesterday the site's workforce might include vandals. A bridge contractor reported to police on Friday that cable wires had been deliberately cut in 32 places along the emergency traffic tunnel underneath the highway's surface. This sabotage had damaged the emergency phone and alarm system. The Highways Department project director for Lantau Link, Lau Ching-kwong, said only someone with a knowledge of the construction's design could have inflicted such damage. 'You need a security pass to get inside and you have to know where the cables are to do any damage,' he said. Mr Lau declined to speculate on motives. But he insisted the link opening would go ahead on May 22.