"Ten districts of Assam are reeling under flood waters which have affected more than 225,000 people. The situation is critical," a statement from the flood control room said.

"More than 1,000 villages were submerged with an estimated 20,000 hectares of paddy under water," it said.

An Assam official said road links between the seven north-eastern states, including Assam, and the rest of India were severed for a third day Sunday.

He said the Brahmaputra river was now flowing three metres (6.6 feet) above its normal level.

"Several thousands are in relief camps," he said. "Temporary shelters are being provided to flood-hit people."

The world's largest river island of Majuli in eastern Assam was inundated and locals were marooned.

"Almost 80 percent of the 70,000-square kilometre (2,800-square mile) island is under water," a local government official told AFP over the telephone.

Rangers at the Kaziranga National Park in Assam, home to the one-horned Indian rhinoceros, were on guard with floodwaters threatening the wildlife sanctuary.

"One third of the 430-square kilometre (172-square mile) park is under water and the endangered wildlife is migrating to nearby hills," the official added.

Despite a forecast of more rain, the weather remained largely dry nationwide for two days, allowing the floodwaters to drop rapidly, flood control officials said.

But they warned that fresh monsoon rains in the upper catchment regions across the border in India's northeast might pose fresh flood threats.

Reports from neighbouring India Monday indicated a slight fall of water levels in the northeastern state of Assam where flash floods left 30 dead and more than 250,000 people stranded.

In Bangladesh, rain-triggered landslides in southeastern Hathazari area near the port city of Chittagong left 13 people dead, while four more were killed by lightning in the eastern Homna area of Comilla district.

Chittagong was pounded Saturday by 134 millimeters (5.36 inches) of rain in just nine hours, disrupting normal life and briefly halting work at the port.

Up to 150,000 people were also hit by flash floods in the northeastern Sylhet region bordering India's Assam state and in the Cox's Bazar district in the southeast on the border with Myanmar, newspapers reported.

Bangladesh is criss-crossed by more than 230 rivers and is prone to severe flooding during the monsoon season.