New Delhi: India's top security officials will meet soon to discuss latest intelligence that Maoist rebels are encircling urban areas, upgrading their weapons and mounting frontal attacks on security forces.

While expanding their influence in the countryside, Maoist rebels are spreading to cities, including the capital New Delhi, through a web of front organisations to boost their network, police said.

Indian Maoists say they are fighting for the rights of the poor and landless, an insurgency that Prime Minister Manmohan Singh has described as India's biggest internal security threat. The rebels have at least 22,000 combatants, armed with light machine guns, automatic rifles and rocket-propelled grenades. Some of the weapons are made in secret factories, officials say.

Security analysts say the rebels, who have a presence in at least 13 of India's 28 states, are consolidating in rural belts outside big cities and towns and building buffer zones.

"Their whole philosophy is to start from villages and move towards cities," said B.K. Ponwar, head of a top counter-insurgency and jungle warfare school.

"The red corridor is expanding and their influence is growing and not reducing at all," he said, referring to a huge swathe of mineral-rich areas controlled by the rebels. The police chiefs of several Maoist-hit states and senior government officials will meet tomorrow to discuss rebel attacks.