The bodies of the soldiers were being flown back from Chhattisgarh
India says it has no plans to deploy troops to fight Maoists, a day after rebels killed 76 paramilitary police.
Home Minister P Chidambaram said central paramilitary and state police forces could deal with the threat, but did not rule out using the air force.
Mr Chidambaram urged calm and patience on a visit to central Chhattisgarh state, where the attacks took place.
Correspondents say it is the worst attack on security forces by the rebels since their revolt began.
An air force transport aircraft has been sent to Chhattisgarh to bring back the bodies of the soldiers killed in the attacks.
State police said the death toll had risen to 76 with the death of another member of the security forces.
Thousands of people have died during the 20-year fight for communist rule.
The Maoists say they are fighting for the rights of the rural poor who they say have been neglected by governments for decades.
Mr Chidambaram laid a wreath near coffins of security force personnel and promised that the offensive against the Maoists would continue.
Mr Chidambaram (right) visited injured troops in hospital
"We must remain calm and hold our nerves to rid India of this threat," he said after meeting relatives of some of the dead soldiers.
"You cannot expect instant success. This is a long, drawn-out struggle. It will take two to three years, perhaps more [to defeat the rebels]."
He said the Maoists presented the "gravest threat to internal security".
"We are paying the price for the neglect of the last 10-12 years," the home minister said. During that time the Maoist movement has grown in strength in large rural areas in eastern and central India.
But he said they would not be allowed to succeed in their long-term aim of overthrowing the government.
India's main opposition party, the BJP, has said there should now be an all-out offensive against the rebels and the media are full of talk of war against the insurgency.
The BBC's Chris Morris in Delhi says the government has always insisted this is not just a security issue.
Our correspondent says it bitterly condemns Maoist violence, but it acknowledges that chronic poverty, and lack of opportunity and development, are significant factors which have given the insurgency added impetus.
Police said the paramilitary troops on patrol in remote jungle in Dantewada district were ambushed by hundreds of heavily-armed insurgents.
Rescue teams were then ambushed in attacks using landmines and gunfire.
An armoured vehicle was first bombed before rebels on a hillock opened fire, police said.
As security personnel took cover, they found the rebels had booby trapped trees with explosives. Troops in the open were gunned down by the rebels.
"We were totally outnumbered. And they [the rebels] had far too much ammunition," Pramod Kumar, one of seven soldiers who survived the ambush, told The Times of India newspaper.
"How could just 80 of us fight more than 1,000 of them? We got no time and no opportunity to retaliate."
The Maoists have stepped up attacks in recent weeks in response to a big government offensive along what is known as the "red corridor", a broad swathe of territory in rural eastern and central India where the Maoist rebellion has been gathering strength.
Nearly 50,000 federal paramilitary troops and tens of thousands of policemen are taking part in the operation in several states.
Mr Chidambaram has said troops will intensify the offensive if the rebels do not renounce violence and enter peace talks.
The rebels want four senior leaders freed from jail and the offensive halted before any talks.