"Information has been received that a water dam has burst again on the Tibetan side," police said in a statement.

"All security personnel, rescue workers, and the general public deployed in rescue and relief operations are requested to remain alert and immediately move to a safe location/report the incident."

The US Geological Survey said the disaster on Wednesday -- the deadliest for Nepal since a 2015 earthquake -- was caused by a glacial collapse that triggered a vast flow of icy debris.

China paused its rescue operation at the hardest-hit part of Tibet over renewed risks of flooding, state media said.

A lake formed by immense piles of debris after a mudslide hit the China-Nepal border has begun overflowing towards the Gyirong border area where rescue teams were headed, Chinese state broadcaster CCTV said.

Nepal's disaster authority spokeswoman, Shanti Mahat, said an initial rise in water had been seen.

"Information has been received that flow of muddy waters have increased slightly in the same area where there was a big flood, in Rasuwa's Bhote Koshi river and there is a risk of further flooding," said Mahat, who works for the National Disaster Risk Reduction and Management Authority (NDRRMA).

"Therefore, all those involved in rescue and relief work on the banks of the Bhote Koshi and Trishuli rivers, and those who are in the risk area for various reasons are specially requested to exercise high alertness and immediately move to a safe place if they see any risk."