Bharti Airtel, India's largest mobile phone operator, and Idea Cellular raised call charges mostly by way of reduction in free minutes or airtime available on most plans.
Price of pre-paid special vouchers that offer services at discounted rates was also hiked while validity period on some recharge coupons reduced.
Other operators like Vodafone are likely to follow suit soon.
Airtel slashed free minutes available in certain plans by 10-25 per cent and hiked price of some call vouchers for prepaid customers by Rs 5-15 (10-30 per cent), market sources said.
The price hike would extend to all of 22 telecom circles in phases, they said.
The hike in call charges come as companies face thousands of crore in one-time surcharge on airwaves they hold beyond a threshhold.
Bharti Airtel said in a statement it has not raised headline tariffs but reduced promotional benefits and free minutes offered to customers. The price change, it said, was in line with the increase in its costs.
"There is no change in the headline tariff. In most circles we have reduced promotional benefits and free minutes on both acquisition and existing usage," the release said.
Idea, India's No 3 carrier by revenue and No 4 by customers, said it had effectively raised voice call prices in some parts of the country after withdrawing promotional offers. The company however did not provide any details.
Vodafone, the country's No 2 mobile phone operator, said it was inclined to follow price moves by competitors "given the sharp input and energy price increases in the country".
"We are inclined to follow to maintain consistency and competitive position though we haven't decided on our precise circle-wise moves," it said.
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