"Sergei Darkin was admitted to the cardiology department of a hospital in Primorye on Thursday," the source said.
Law enforcement officers confiscated a safe containing documents during the raid on the governor's home. Local administration officials have so far declined to comment.
The search was conducted in connection with a criminal investigation into the illegal privatization of state property in Vladivostok, the administrative center of the Primorye Territory, at below-market prices. In total, the federal budget is said to have lost over 1.5 billion rubles ($64 million).
The source also claimed that Darkin, 45, had given a statement in the local prosecutor's office before the search of his house on Wednesday.
The official is said to have testified in connection with an ongoing investigation into activities of the acting head of the Federal Property Management Agency, Igor Mesheryakov, who has been accused of large-scale fraud.
In January Sergei Sopchuk, a first deputy governor of Primorye, was wounded by an unidentified gunman in an apparent assassination attempt. Primorye Governor Darkin called the attack on Sopchuk an "attempt to intimidate both the authorities and society."
