A food shortage has hit nearly 70 percent of a remote Indian state's people after an army of rats began devouring rice crops and triggered a famine scare, officials said Friday.

The northeastern state of Mizoram had a devastating famine in 1959 when a rare flourishing of bamboo flowers — a favorite food of the rodents — drove up their numbers.

The phenomenon occurs about every 50 years and has hit the state again.

This year the food shortages have affected about 630,000 people, nearly 70 percent of the 900,000 in Mizoram, said the state's Food and Supplies Secretary T.B.C. Rozara.

No starvation deaths have been reported so far, he said.

"Rats multiply in abundance whenever the rare bamboo flowering occurs as they feed on these flowers and then go about feasting on standing crops and granaries," said another state official, L.R. Sailo.

In the past year farmers in the state harvested only a fifth of the expected rice production of 142,580 tons. They got enough for just two months' consumption, Rozara said.

He said Mizoram has sought $154 million in assistance from the federal government and is considering offers of help from the United Nations and other international agencies.

"We need 15,000 metric tons (16,535 US tons) of rice a month to prevent hunger in the rat-affected population. This is a huge challenge," Rozara said.

Federal authorities were rushing to distribute rice to the poor at low prices and state officials were giving free rice to those with no money, Rozara added.

He said some residents were buying rice across the border in Myanmar.

In 2007 state authorities introduced a "kill a rat, get cash" program. They offered 5 US cents for each rat killed in the state and supplied free rat poison to about 10,000 farmers.

But that did not prevent the latest shortage.

"The situation is grave and we are having sleepless nights. But we hope to deal with the problem," Rozara said.