KATHMANDU, Nepal — Catastrophic floods on the China-Nepal border have killed at least 1,252 people in Nepal, the disaster authority said Thursday, taking overall deaths to more than 1,270. Chinese state media earlier confirmed 21 people were killed in Tibet, bringing the total toll from the disaster that struck on August 26 to 1,273. The number of missing in Nepal remained 4,216, as rescue operations continued on a war-footing. In China, state media say there are 541 people missing, taking the overall number to 4,757. Nearly 600 foreigners from over 30 nationalities are also missing, with Indians making up one of the largest proportions. Some 75 Americans are also unaccounted for, according to the State Department on Wednesday. In Kathmandu, desperate families of some of the missing foreigners said they were combing hospitals and morgues for any information about their loved ones. "I feel desperate, it's been so many days," said 53-year-old American Sanjeev Rai who flew to Nepal after learning that his wife was untraceable. The floods, which tore through mountain districts, have destroyed