The race was on at snowbound European airports to clear the backlog of stranded passengers in time for Christmas as weather conditions eased slightly. Thousands of weary passengers woke up in airport terminals around the continent, where stranded travellers have been bedding down since Friday. Hopes of making it to their destination before Christmas Day were lifted at London Heathrow Airport after the second runway reopened, but the backlog at a traditionally busy time of the year meant services were not immediately back to normal. A Heathrow airport spokeswoman said the airport was absolutely aiming to get everyone away in time for Christmas. Weather reports said snow could persist in northern Europe, which might hamper flight operations at airports that feed flights into key European hubs. In France, authorities allowed the two main airports in Paris, Charles de Gaulle and Orly, to remain open around the clock to clear the backlog of delayed flights. Around 15 per cent of flights at Charles de Gaulle were to be cancelled from this afternoon and 25 per cent tomorrow. Operations at Frankfurt airport, Germany's main hub, were improving though 70 early flights were cancelled. Unions representing ground staff for Portuguese carrier TAP announced they had called off a strike due tomorrow to avoid aggravating the continent's Christmas travel crisis. While rail services across Europe were also affected, the situation was improving on the Eurostar, which operates high-speed passenger trains linking London with Paris and Brussels. News Agency reports said, in Russia, eight people were killed when a bus smashed into an oncoming truck in the western Siberian region of Krasnoyarsk. Investigators said the accident may have been caused by a technical malfunction resulting from the cold weather, with temperatures dropping to minus 50 degrees Celsius. Southern Sweden was experiencing problems on its road network because of unusually heavy snow.