A boy has died from highly lethal anthrax disease in Russia's northwestern Siberian region of Yamal, while 90 other people were put under observation in hospital, Russian news agencies reported Tuesday.

On Monday, a 12-year-old boy died after being diagnosed with anthrax, said TASS.

"Currently, in the hospital of the city of Salekhard, there are 90 people brought from the hotbed of the outbreak," TASS quoted Natalya Khlopunova, a spokeswoman of the Yamal region's governor, as saying.

An outbreak of the highly infectious disease has killed 2,349 reindeer, while more than 35,000 reindeer out of 700,000 had been vaccinated against the disease by Tuesday, the local government said in an online statement.

A state of emergency has been declared in the Yamalo-Nenets Autonomous District, where currently 44 veterinary physicians were controlling the situation and more were expected to arrive shortly, the regional government said.

Interfax news agency on Tuesday quoted Anna Popova, head of the consumer rights watchdog Rospotrebnadzor and the country's chief epidemiologist, as saying that the anthrax hotbed had been contained.

"The hotbed for people has been contained. But all measures will continue until we vaccinate all animals and are totally certain of people's safety," Popova said, adding that there was no threat of the disease spreading to other regions.