"We are concerned over Maoist activities in parts of nine districts of Assam. Their presence is in 35 police station areas of the districts," Gogoi told reporters here.
"We have been keeping a strict vigil on the Maoists since 2006 and that is why they have not been able to step up their activities in the state as much as they would like", he said.
A close watch was kept on particularly in the areas where poor people lived as Maoists attempted to make inroads in the districts, he said adding that under surveillance were also the activities of suspected sympathisers of the Maoist rebels.
The nine affected districts are Dibrugarh, Tinsukia, Jorhat, Sibsagar, Golaghat, Lakhimpur, Dhemaji, Cachar and Karimganj, he said.
Due to the alertness, four Maoists were killed in encounters with police and 58, including two top national level leaders, arrested recently, he said.