Up to an extra 300 security officers are being hired at Chek Lap Kok to carry out additional searches on aircraft and baggage following the terrorist attacks. The airport's aviation security general manager, Sidney Chau Foo-cheong, said the extra manpower was needed after airlines had requested the extra precautionary measures. 'We have 2,700 staff on duty every day,' Mr Chau said. 'They have already been asked to cancel their holidays. We've asked them to increase vigilance and step up patrols at the airport. 'We're hiring more staff. We need an extra 200 to 300 staff to carry out extra services for airlines over the next few days.' The additional cost will be paid by airlines. As well as X-ray screening of hand luggage, Mr Chau said some airlines had requested their officers to conduct a hand search on baggage and even body searches on passengers leaving for Europe. Mr Chau expected more airlines to make the same request once flights between Hong Kong and the US fully resumed. It is standard practice for all check-in luggage at the airport to be X-rayed, but Mr Chau said they were discussing with airlines the need to open bags for a double check. The demands of the airlines will determine how long the extra security guards will be needed. Mr Chau said they would also study reports from the US on how the four planes were hijacked to see what lessons could be learned. 'We'll always stay on the alert,' he said. Travellers in Hong Kong heading to the US and Canada have been told to arrive at the airport three hours before their departure times for extra security checks which were required by the US Federal Aviation Administration yesterday as flights to the US and Canada slowly resumed. Passengers leaving for the two countries will only be allowed to check in at the airport and will be restricted to one item of hand baggage. They will also not be allowed to carry knives. Cathay Pacific urged passengers to be patient. 'Enhanced security measures mean clearing security and immigration will take longer than previously,' a spokesman said.