"As they are trying to create panic in the run up to April 7, the police and the security forces have been placed in vulnerable areas to thwart their design," state Director General of Police Jayanta Narayan Choudhury said.
"Besides Sibsagar, Dibrugarh, Tinsukia and Jorhat in upper Assam, the ULFA cadre may also resort to violence in lower Assam districts of Darrang and Goalpara," Choudhury said.
Recent events, he said, have pointed to the growing nexus between the ULFA and Maoists.
"The bomb that exploded in Doomdooma town in Tinsukia district on Saturday night was inside a tiffin box but the involvement of Maoists in the incident cannot be ruled out," he said.
The DGP said while top ULFA leader Dristi Rajkhowa was currently holed up in Goalpara district bordering Meghalaya, two hardcore ultras Babul and Pradeep Gogoi were in upper Assam.
The ULFA last week had ambushed a BSF patrol party in Goalpara-Kamrup Rural border injuring one jawan.
Even Arabinda Rajkhowa, the chairman of the pro-talk faction of ULFA, had last week expressed apprehension about strikes by the hardliners, headed by its commander-in-chief Paresh Baruah.
The ULFA was formed on April 7, 1979, at the Rang Ghar in Sibsagar.