Maoist rebels in eastern India killed at least 76 paramilitary troops Tuesday, authorities said, underscoring the continued strength of an insurgency that India has tried for decades to wipe out. The dawn attack in Chhattisgarh state was among the deadliest by the guerrillas in memory.

S.R. Kalluri, a deputy police inspector in densely forested Dantewada district, where the attack occurred, told local reporters that the troops were on an extended patrol and stopped to rest Monday night.

Insurgents learned of their location and “at the break of dawn the Maoists attacked,” Kalluri said. “Now we are chalking a strategy to retaliate.”

Several thousand people have died in attacks since the Maoist insurgency began in the late 1960s. The rebels are said to number about 20,000, including an estimated 6,000 hard-core combatants.

In recent months, they have stepped up their attacks in response to a police offensive initiated late last year across several “red corridor” states. On Sunday, rebels set off a land mine that killed at least 10 members of an elite anti-Maoist unit in the mineral-rich eastern state of Orissa.

The rebels are funded in part by hundreds of millions of dollars extorted from companies each year. Their arsenal includes automatic rifles, shoulder-fired rocket launchers, mines and related explosives, some of which have been stolen from Indian authorities and some purchased from Chinese smugglers.

The Maoists, who say they are fighting for poor farmers and landless workers, are particularly strong in impoverished, rural areas where basic government services are limited and local corruption is endemic. India’s expanding middle class displays its affluence in the cities, clogging roads and crowding shopping centers, but vast swaths of the country have not shared in the economic gains.

Home Affairs Minister P. Chidambaram said an evident intelligence failure allowed the patrol, a joint operation of state and central government forces, to walk into a trap. Monday was reportedly the second night that the paramilitary units had been camping out in remote jungle terrain.

Police spokesman R.K. Vij estimated that 1,000 rebels took part in the attack; others put the number closer to 300.

Although the central government has claimed progress in its Operation Green Hunt campaign against the Maoists, the number of attackers and their ability to avoid detection suggest that the government faces a tough fight. More than 1,000 attacks, resulting in 600 deaths, were recorded last year.

“They will hit you where you are the weakest and run and hide when you are strong,” said Ajai Sahni, executive director of the New Delhi-based Institute for Conflict Management, a think tank. “It is the basic principle of guerrilla warfare. . . . The government needs to stop telling people about massive deployments and giving sound bites to the media. It needs to develop a strategy.”

mark.magnier

@latimes.com

Rana is a special correspondent.