More livestock have died in East Siberia's Republic of Buryatia, where 11 people have been hospitalized with suspected anthrax, Russia's chief sanitary official, Gennady Onishchenko, said.

Onishchenko told reporters on the sideline of the G8 summit in Japan's northern island of Hokkaido that the outbreak was caused by violations in sanitary regulations.

"Today the deaths of horses and livestock were recorded," Onishchenko told journalists.

Last week, nine people were hospitalized in the republic's Barguzinsky Region with the suspected disease after culling a sick bull. The meat was then sold without any checks being carried out.

"It was given to a businessman and he sold it in four villages," the official said, adding that a total of 200 people could have been exposed to the disease.

As a result, seven people have been officially diagnosed with skin or intestinal anthrax. They are currently receiving medical treatment for the disease. One person is in a serious condition.

Anthrax most commonly infects wild mammals and domestic cattle and sheep, which ingest or inhale the spores while grazing. Humans can be affected when exposed to blood and other tissues from infected animals.

Anthrax spores can survive for long periods of time in the environment after release. Russia has over 100,000 potentially dangerous sites, several of them are located in Buryatia.