A Kremlin-linked Web site on Wednesday leaked a video clip of an angry President Vladimir V. Putin threatening to dismiss top officials, fueling speculation that Mr. Putin may be preparing to replace Prime Minister Dmitri A. Medvedev and his cabinet.

The video was published hours before Mr. Medvedev was to report to Parliament, a yearly event in which he is expected to respond to criticism. Mr. Putin’s press secretary called the leak “unacceptable from an ethical standpoint,” but politics here takes place amid onionskin layers of artifice, and many analysts concluded that the Kremlin intentionally released it as a warning shot to Mr. Medvedev.