The Red Cross on Wednesday boosted its estimate of the cyclone death toll in Myanmar to as many as 128,000 — a much higher figure than the government tally. The U.N. warned a second wave of deaths will follow unless the military regime lets in more aid quickly. The grim forecast came as heavy rains drenched the devastated Irrawaddy River delta, disrupting aid operations already struggling to reach up to 2.5 million people in urgent need of food, water and shelter.

“Another couple of days exposed to those conditions can only lead to worsening health conditions and compound the stress people are living in,” said Shantha Bloemen, a spokeswoman for UNICEF. A tropical depression in the Bay of Bengal added new worries, but late in the day forecasters said it was weakening and unlikely to grow into a cyclone.

Myanmar’s government issued a revised casualty toll Wednesday night, saying 38,491 were known dead and 27,838 were missing.