VLADIVOSTOK, Russia, Oct 1 (Reuters) - Russia's far eastern Khabarovsk region appealed for urgent government help on Monday as forest fires raged through thousands of acres of land, endangering residents and forcing the local airport to close. Doctors warned Khabarovsk dwellers not to leave home and to seal their windows to protect themselves from toxic fumes, as the fires closed in on densely populated regional centres. "The most difficult situation is in the Lazo district, where the affected areas total 41,395 hectares (102,300 acres)," an official from the Khabarovsk administration said. Khabarovsk airport was closed after thick smoke reduced visibility on the runway, and aircraft were redirected to nearby aerodromes. Local meteorologists said no rain was expected in the region within the next few days. It was unclear why, or when, the blazes started.