Oleg Mitvol, deputy head of the Federal Service for the Oversight of Natural Resources (Rosprirodnadzor), told the Interfax news agency that the agents inspected documents in the accounting offices.
"Financial documents regarding business trips taken by our staff members are in fact being confiscated from our accounts department now," he said.
He added that the investigators "have the right to do it. The only thing that upsets us that it concerns those staff members who took part in our most recent [environmental] inspections
Citing environmental violations, Mitvol last month revoked a key environmental permit allowing Royal Dutch Shell to explore and produce gas on Sakhalin Island.
(Interfax, AP, dpa)