"According to some information, North Korea launched 10 missiles of different classes," Chief of the General Staff Yury Balyuevsky, adding that they could have been intercontinental ballistic missiles.
Initial reports suggested six missiles had been fired.
North Korea officially announced Wednesday that it had conducted test launches of ballistic missiles and claimed it was the country's sovereign right. The communist nation launched the missiles, including a long-range Taepodong-2, despite a moratorium on missile tests.
According to the Japanese military, all the missiles fell into the northwest of the Sea of Japan.
Baluyevsky said Russian systems had confirmed missile launches but cautioned that the Russian military was processing data on the quality and characteristics.
He said he would learn the class of missiles after he had received technical control data.