A leading Russian journalist has been badly beaten outside his apartment in Moscow, prompting President Dmitry Medvedev to order a police investigation.

Russia is one of the world's most dangerous countries for journalists, and his colleagues say they are certain Saturday's attack on Oleg Kashin was politically motivated.

His editor said the attack was probably linked to Kashin's coverage of banned opposition groups.

Kashin was left with a fractured jaw, broken legs and fingers, and severe concussion.

Al Jazeera's Jonah Hull reports.