By Mark Dummett
BBC News, Dhaka
A plague of rats has destroyed the crops of tens of thousands of people living in Bangladesh's remote Chittagong Hill Tracts.
The rat plague is expected twice a century
Aid workers have warned that the destruction of crop has left the people in a "near-famine situation".
The rat population has soared in recent weeks as they feed off the region's bamboo forests, which are blossoming for the first time in decades.
Neighbouring states in India have suffered from the same problem.
According to the UN Development Programme (UNDP) about 150,000 people living in the hills along the country's south-eastern border with India have been affected.
Prasenjit Chakma of the UNDP, who has visited the area, told the BBC that people there had been reduced to eating roots to survive, but even these are now running out.
He said fields had been stripped of their plants, and are now dotted with large rat holes.
"The rats are much bigger than usual. They eat everything that is fresh and green," he said.
The rodents have multiplied at an alarming rate - the bamboo blossom is such a good food source for them that when they eat it they can breed up to eight times a year - four times more often than normal.
According to local folklore, the flowering of the bamboo, and the subsequent surge in rat numbers, occurs every 50 years.
They say the last time it happened was 1958.
People across the border in India share this same belief - and the same problem.
In Mizoram state, the bamboo began to blossom last year.
The government there declared it a disaster zone after the rats went on to eat people's food stocks.
Here, the authorities and relief agencies have begun to get some aid to the hungry, but they admit it is not yet enough, and that the problem is spreading, as more forests start flowering.
Mr Chakma said the region will face problems for the next three to four years, until the rat population declines.
He said there are so many of them, it is difficult for the farmers to kill enough to make a difference.
"The situation is very serious. The people living in that region are very poor anyway. It is now a near famine situation," he said.