A probe by security agencies has revealed “procedural lapses” and intelligence failure that resulted in the massacre of 22 security personnel in Chhattisgarh early this month, sources said on Saturday.

The Maoists had ambushed and killed the jawans inside the forests on the Bijapur-Sukma border in a four-hour gun battle with the security forces.

“The report has revealed grave procedural lapses on the part of the top brass of the CRPF and Chhattisgarh police in launching an offensive against the ultras inside the jungle. According to the standard operating procedure, the forces should not have advanced into the forest without carrying an area domination exercise,” said a security official attached to the Union home ministry.

He said it was a blunder on the part of the top brass, especially the commanders as they failed to read the telltale signs of the impending attack.

“They walked into a trap meticulously planned by the Maoists resulting in a huge casualty. There was also complete intelligence failure as the security personnel did not anticipate the presence of over 250 rebels who surrounded them from all sides and started firing,” the official added.

According to SOP, the road opening patrol team, which provides security to the troop movement, is usually sent to secure the area.

On April 3, around 2,000 security personnel had launched a concerted operation in Maoist-hit Bijapur and Sukma districts after learning that rebels led by the dreaded Madvi Hidma had gathered in the forests in large numbers.

“The CRPF top brass has been asked to submit a detailed report on the encounter and also the names of the commanders who had led the operation,” a home ministry official said.

The CRPF reports to Union home minister Amit Shah.

CRPF director-general Kuldiep Singh has denied any lapses.

Eight of the dead jawans were from the CRPF — seven from the elite Cobra commando unit — while the rest were from various state police units.

This was the highest casualty the security forces have suffered at the hands of the insurgents since April 2017 when rebels ambushed and killed 25 CRPF personnel near Burkapal in Sukma.