Insurgent group, Maoist has killed 22 police officers in an ambush over the weekend in India, a top police officer said on Monday.

At least 30 other members of the security forces were wounded in the four-hour gun battle with Maoist rebels that took place in Chhattisgarh state on Saturday, the deadliest ambush of its kind in four years.

"The operation will be intensified," said Om Prakash Pal, Deputy Inspector-General of police, who is leading the fight against the rebels in Chhattisgarh.

The Maoists, also known as Naxals, have waged an armed struggle against government forces for decades.

They say they are fighting for the poor, who have been left behind in India's economic boom.