A leading Russian environmental activist said on Friday he had been hospitalized after being severely beaten by unknown assailants in the southern city of Krasnodar. Andrei Rudomakha, head of the Environmental Watch on the North Caucasus NGO, told Reuters he and a group of activists were assaulted late on Thursday upon returning from the Black Sea coastal city of Gelendzhik where they were documenting the illegal construction of a mansion for high-ranking officials. The regional branch of the Russian Interior Ministry, in a statement sent to Reuters, said authorities were investigating the attack by what it said were three assailants.