An alert has been sounded in all seven districts of the Naxal-hit Bastar division in Chhattisgarh following the deadly attack by Naxalites in Dantewada which claimed the lives of 10 police personnel and one civilian, police said on Thursday. Security forces have been asked to stay cautious while moving in a vehicle and conducting de-mining exercises to detect the Improvised Explosive Devices (IEDs) planted by Naxalites after the attack on Wednesday, they said.