Two of those killed were civilians, TASS reported citing Armenian media.
Apart from that, more than 210 people, including 12 children, were wounded.
Azerbaijan on Tuesday launched a military operation in its breakaway Karabakh enclave, nearly three years after fighting a brief but brutal war with Armenia over the mountainous region.
While Azerbaijan says it is not targeting civilians, Armenian sources claim that so far 210 civilians are among the casualties including 12 children.
AMK/PR