"The government strongly condemns this unprovoked and heinous attack by the CPI (Maoist) on a public sector security force that was on a routine patrol in an area falling under the jurisdiction of a public sector corporation," the Home Ministry said in a statement.

It noted that the CISF team was on routine patrol of the area under a public sector undertaking, National Minerals Development Corporation (NMDC), which is engaged in development of minerals, gives employment, promotes economic activity, and undertakes many welfare activities in the area as part of its corporate social responsibility.

The Ministry questioned "not only the CPI (Maoist) but also to those who speak on their behalf and chastise the government" as to what was the motive behind the attack and what is the message the CPI (Maoist) intends to convey.

Four CISF personnel, inclduing a sub-inspector, a head constable and two constables, were killed and two others were critically injured in a landmine blast in the mines area of NMDC in Bacheli in Dantewada yesterday.

The Home Ministry said it has also received reports of an incident in Kanker district in the state on October 21 in which 100 naxalites abducted five villagers. While two of them were released, two were killed.

"The Chhattisgarh police is investigating the crime. This is yet another case of cold blooded murder of poor villagers by naxalites," the ministry said.