With time running out for sick and starving survivors in cyclone-ravaged lowlands, thunderstorms and rough weather Monday hampered relief efforts and escalated fears the death toll could rise sharply.

"The critical period has started. Famished men, injured men can only survive for four to five days under the circumstances," said Dr. Mohammad Musa of CARE International, a worldwide aid group.Official reports say more than 125,730 people have perished following last Tuesday's cyclone that swamped coastal areas with huge waves and winds up to 145 mph. An estimated 10 million people were left homeless by the cyclone, one of the worst to hit Bangladesh this century.

The Red Crescent - the Islamic equivalent of the Red Cross - predicted the death toll would probably reach 200,000 from starvation and diseases spread by water fouled by rotting animal carcasses and sewage. Newspaper reports said the final toll could hit 500,000, which would exceed the aftermath of a 1970 cyclone that hit the nation on the northern coast of the Bay of Bengal.

"We don't see how they can avoid one of the biggest cholera epidemics in the century," said John Mohrbacher, a spokesman for CARE in New York.

"The situation has become worse and we are very worried," said Emdasd Hossain, director of the Red Crescent Society's Cyclone Prepardness Program.

The thunderstorms and rough seas Monday delayed two rivercraft and four trucks carrying supplies to the east coast, CARE reported. Gusty winds and rain on Sunday hampered Bangladesh's fleet of 17 helicopters and a few fixed-wing airplanes on missions to airdrop supplies.

CARE officials said a relief convoy was stranded with 35 personnel in Comilla, 70 miles north of the devastated port of Chittagong.

"The weather is pretty bad. It is holding up and hampering our relief operations," CARE's Bangladesh Deputy Chief Robin Needham said.

There were no immediate reports of injuries or damage from the thunderstorms, which hit as hundreds of thousands of people huddled on spits of land isolated by floodwaters.