Chhattisgarh went on top alert in the wake of the killing of 31 people by Naxalites in Dantewada and a two-day bandh called by the ultras from Tuesday to protest the anti-Maoist operations by the security forces.

A day after the deadly Naxal attack, in which civilians and special police officers travelling in a bus were killed in landmine blasts, combing operations were intensified in the Dantewada region.

Security forces were on high alert in view of the bandh called by the Naxals in Chhattisgarh, Orissa, Bihar, West Bengal and Jharkhand.

The Centre had yesterday asked all the five States to tighten security and take maximum precautions during the bandh. The railways have also been advised to run trains in Naxal-affected areas at slow speed to avoid possible sabotage of tracks and bridges, according to Home Ministry sources.

Though Chief Minister Raman Singh had yesterday put the toll in the attack at 35, Dantewada Superintendent of Police Amresh Mishra said the toll was 31, including 16 police SPOs and some policemen, with one SPO succumbing to his injuries this morning.

Naxals had earlier warned private vehicles against accommodating security forces. After the incident, panic-stricken private bus operators in the area were this morning refusing to take out their vehicles.

A private commercial bus ferrying passengers from Dantewada to Sukma was blown up between Gadiras and Bhusaras near Chingavaram village, about 450 KMs from here, yesterday with the Naxals detonating improvised explosive device containing gelatin sticks planted on the metalled road.

The bus was targeted after the Naxals got to know that SPOs were on the bus. Some of the SPOs were also said to be travelling on the rooftop of the bus.

According to senior police officials, the Naxals had opened fire after triggering the IED. 47 rifle cartridges were recovered from the spot indicating that the military wing of the Naxalites were involved in the attack and the ultras wanted to kill the surviving victims.

State Police Chief Viswa Ranjan had yesterday said about 100 SPOs had gone to Dantewada on May 15 for an anti-Naxal operation. Some of them returned by bus. Under the Standard Operation Procedures, security personnel have been advised not to use civilian vehicles.

SPOs are mostly local people recruited to fight the Maoists and have emerged as the biggest threat to them.

Strongly condemning the attack, Union Home Minister P. Chidambaram had said the Centre will have to re-look at its strategy deal with the Left Wing extremists.

Chhattisgarh Chief Minister had said he would urge Prime Minister Manmohan Singh to re-examine the strategy to tackle the Naxals, who were targeting innocent civilians.

While this is the first such attack on a civilian passenger bus, on April six Dantewada had witnessed the worst-ever massacre of 75 CRPF jawans and one policeman in a Naxal ambush.

The Home Ministry has called a meeting in Delhi to review the situation. Union Home Secretary G.K. Pillai had said the killing of innocent civilians showed “wanton disregard” for life by Naxals.

“This pattern of killing unarmed civilians has been the hallmark of Maoist violence over the years. In the last two days, we have seen that a village sarpanch and five others were killed,” Pillai had said.