Official sources said the Prime Minister and Union Home Minister Shivraj Patil rang up Mr Bhattacharjee and enquired of the incident in which six policemen were injured, three of them critically.
The landmine was believed to have been detonated by Maoists targeting the Chief Minister, who along with Steel Minister Ram Vilas Paswan was on his way back to Kolkata from Salboni after laying foundation of an integrated steel plant of JSW Steel.
While the Ministers escaped unhurt, six policemen, travelling in the last car of the convoy, were injured.
Police found a 2.5-km-long wire, believed to have been used as the detonator, which had been attached to the landmine.
''So far, six persons have been arrested for their suspected links with the Maoists,'' Inspector General of Police (Law and Order) Raj Kanojia said.
Director General of Police (DGP) Anup Bhushan Bhora, who visited the site, said, ''A high-level committee, comprising senior police officials, reached the explosion site during the day and started its investigation.'' Chief Security Advisor A K Maliwal and other senior police officials were assisting the inquiry, while forensic teams also reached the place.
''The nature of the explosion and all sides of security lapse are being probed and if any police official is found to have been negligent in his duty, appropriate action will be taken up,'' the DGP said.
''New types of explosives and splinters, which had never been used earlier, were used in the landmine. It is suspected that Maoist ultras were responsible for the incident,'' Mr Maliwal said.
A team of forensic experts, headed by DIG (CID) Shibnath Gupta, was presently investigating the site to ascertain the nature of explosion and type of chemicals used and would submit a report to the state government by this evening.
The Maoists had dropped pamphlets in the district in the past and urged the villagers not to give land for the Jindals' project.
UNI KDG SJC PK HS1921