An unidentified male assailant has rushed into the Moscow headquarters of news radio station Ekho Moskvy and stabbed a deputy editor in chief and anchor, Tatyana Felgengauer.
Ekho Moskvy editor in chief Aleksei Venediktov wrote on Twitter that the attacker struck Felgengauer in the throat with a knife in the October 23 attack.
The Investigative Committee has opened a criminal case into charges of attempted murder.
The attacker was detained by station security personnel, while Felgengauer was hospitalized in serious, but non-life-threatening condition.
He said that police are working at the scene. No more details were immediately available.
Venediktov said the assailant rushed past station guards after spraying them with a chemical.
It is unclear how the assailant made it to the station's offices on the 14th floor. The crowded building has only two public elevators that are notoriously slow.
Venediktov told RFE/RL that the attacker went directly into the room where Felgengauer was sitting.
"He knew the layout of the rooms at the station," Venediktov said. "There can be no doubt about that."
"The attacker didn't shout anything," station deputy editor in chief Sergei Buntman told the Meduza website. "Everything was quiet. He just walked up to her, grabbed her, and stabbed her."
The Uzbekistan-born Felgengauer, 32, is stepdaughter of the well-known Russian journalist and military expert Pavel Felgenhauer. She has worked at Ekho Moskvy since 2005.
Owned by a Kremlin-controlled Gazprom natural gas company, Ekho Moskvy is one of the few remaining independent media outlets in Russia. It has managed to avoid being targeted for criminal investigations, which are often used in Russia to silence media.
Journalists frequently come under attack or are harassed in Russia. In September, Ekho Moskvy journalist Yulia Latynina fled Russia after being attacked and threatened in Moscow.
Political analyst Yekaterina Vinokurova wrote on the social-media site VKontakte that "Tanya and Ekho Moskvy have been under assault for years."
"They have attacked journalists from the station," Vinokurova wrote. "They have hung banners with their photos saying they were 'enemies of the people,' 'agents of the [U.S.] State Department, and so on. There has been all sorts of garbage about them coming from state television.... Now we have come to this and they shameless are talking about the motive of 'hooliganism.'"
Physical attacks on Russian opposition figures and journalists are often investigated under the relatively lax law against "hooliganism," rather than as assaults or attempted murder.
Vsevolod Bogdanov, chairman of the Russian Union of Journalists, condemned the attack on Felgengauer.