"Aviation monitoring today … discovered a new concentration of saiga deaths with the approximate number of dead animals reaching beyond 400," the agricultural ministry announced Thursday.
Earlier it had said 540 carcasses of saiga antelopes had been found in the Kostanai region of Kazakhstan, before the finding of the additional animal carcasses, RIA Novosti reported.
Last year, at least 12,000 saiga died in western Kazakhstan, presumably from pasteurellosis infection, officials said.
Saiga were virtually exterminated in the 1920s because of hunting and the high demand for their horns in Chinese medicine.
Their numbers recovered in the Soviet Asian republics in the 1950s, and current estimates put the number of saiga in Kazakhstan at 85,500.
In November 2010, Kazakhstan introduced a ban on saiga hunting and spends $800,000 annually on conservation efforts, officials said.