The death toll from rain-triggered mudslides in Zhouqu County in northwest China's Gansu Province had risen to 137 as of 4:07 p.m. Monday with 1,348 still missing, the provincial civil affairs department said Monday. Rescuers are racing against the clock in the search for survivors in the debris of the town flattened by mudslides early Sunday morning, Xinhua reported. Some 117 people were injured, of whom 28 were severely wounded. Four of them are in critical conditions, according to the provincial health bureau. Four helicopters carrying 20 severely injured residents arrived at a military airport Monday afternoon in Gansu's capital city, Lanzhou, some 650 km from Zhouqu, for admittance to better-equipped hospitals. Twenty more patients will be sent to Lanzhou by Tuesday. About 45,000 residents have been evacuated, as mudslides have destroyed more than 300 homes and damaged another 700. Moreover, 3,000 homes have been flooded. The Ministry of Civil Affairs dispatched 5,000 sleeping bags to Zhouqu. The ministry has sent four batches of relief supplies, including 5,200 tents, 20,000 cotton coats, and 8,000 folding beds, to Zhouqu.