"The broken cable has been restored. Now the operator is testing the communications line together with [Russian space agency] Roscosmos," spokesman Denis Rychka of the telecom firm Akado said.
Construction workers severed the cable serving the Russian mission control center at Korolev near Moscow Wednesday, RIA Novosti reported.
Three teams were deployed to the site outside Moscow to repair the cable, Rychka said.
The incident had not interfered with communications with the Russian segment of the International Space Station, Roscosmos said, and the Russian Defense Ministry said its military satellites were also not affected as it possesses its own communications channels.