Raging wildfires in recent weeks killed 34 people, the emergencies minister said Tuesday in a new toll as President Vladimir Putin visited the stricken region.
"To date, 34 people have died in southern Siberia," Emergencies Minister Vladimir Puchkov told Putin in a meeting to address the disaster. Another 77 were hospitalised, some with serious burns.
The fires have destroyed about 2,000 homes, Putin said, as he announced financial assistance for those affected, pledging their houses would be rebuilt by September.
He also warned that justice would be meted out.
"We have to see who was in charge of what and what they have to be held responsible for," Putin told a group of residents who had lost their homes.
"If someone is guilty of something, they must answer for it."
Russia's Investigate Committee, the main federal investigation authority, announced soon afterwards that a regional fire prevention official has been detained for possible negligence.
Earlier this month emergency officials in the region said the fires were started by people burning dry grass and went out of control due to strong winds.
Putin's representative in Siberia, Nikolai Rogozhkin, last week blamed the fires on specially trained "opposition" activists.
"Some opposition group has gathered... They received instructions and performed acts of sabotage by setting certain locations on fire," Rogozhkin was quoted as saying by local media.
The fire started in southern Siberia, crossed the border with Mongolia and travelled another 200 kilometres (120 miles) to the Chinese border, where it finally died out, according to Greenpeace's Russian section, which published satellite images on its website.
Reports in US media said Monday that smoke from the fires has crossed the Pacific Ocean and was colouring sunsets on the West Coast a deep red.
© 2015 AFP