Desperate relatives braced for bad news Monday as rescuers dug through landslides in the wake of severe floods that have killed 100 people and left swathes of central and western Japan underwater. As floods receded, emergency workers were able to reach previously cut-off places where authorities fear they could find more bodies in the wreckage of homes devastated by rivers of mud and debris, AFP reported. "I have asked my family to prepare for the worst," said Kosuke Kiyohara, 38, as he waited for word of his sister and her two young sons. "I cant reach her phone," he told AFP, sitting across from a house that had been ripped apart and tossed on its side by a huge landslide. "A total of 73,000 police, fire department, Self-Defence Forces and Japan Coast Guard personnel, with 700 helicopters, are doing their best as part of the rescue effort," government spokesman Yoshihide Suga said. "Rescue efforts are a battle with time," Prime Minister Shinzo Abe told reporters. "The rescue teams are doing their utmost." The assessment of casualties has been difficult due to the vast area affected by the rainfall and flooding, as well as landslides. According to AP, authorities warned that landslides could strike even after rain subsides as the calamity shaped up to be potentially the worst in decades. Even as the rains recede, authorities warned the downpours had loosened earth on hillsides and mountain slopes creating new risks. "We urge residents to remain cautious about possible landslides," a weather agency official told AFP.