President Medvedev has returned from holiday for a crisis meeting over the Russian wildfires that have now killed at least 48 people.
He has sacked several navy commanders for failing to control a fire that ravaged a military base. There is also concern about the threat to a major nuclear research centre.
Troops are among tens of thousands fighting more than 500 fires across central Russia. Seven regions are still under a state of emergency.
After fire destroyed several military hangars at a navy base near Moscow, the navy’s head was reprimanded and other officers were dismissed.
President Medvedev said the Defence Ministry was incapable of protecting itself, never mind the population at large.
The Sarov nuclear research centre is where the first Soviet atom bomb was designed.
More than two thousand firefighters are battling fires nearby. The head of Russia’s nuclear agency said the situation was under control.
Thousands have been left homeless in the hottest summer since records began.
Smoke from the forests has reached Moscow, where the authorities have told people to stay indoors.
Critics say the government has been slow to respond. They also claim fire protection measures in Russia’s vast woodlands have been weakened after lobbying from the timber industry.