The editor in chief of Ekho Moskvy radio, Aleksei Venediktov, says he found a chunk of timber with an ax embedded in it outside his apartment door in Moscow as he returned home today in the early morning hours.
Investigators say the incident might represent a threat to Venediktov and could be connected to his professional activities.
Talking to RFE/RL's Russian Service, Venediktov said neither he nor members of his family would comment on the incident.
Ekho Moskvy is one of the few independent media outlets in Moscow.
The incident comes after a string of murders targeting journalists in Russia.
The latest was in late January, when "Novaya gazeta" journalist Anastasia Baburova was shot and killed
on a Moscow street.