India's top mobile phone firm Bharti Airtel reported Wednesday a worse-than-expected 28 percent dive in quarterly profit, hit by the costs of its Africa acquisition and investments in 3G.Net profit slid to 12.15 billion rupees ($273.8 million) for the fiscal first quarter from a year earlier, the sixth straight quarterly profit drop, but revenues rose 39 percent to 169.75 billion as Bharti added new customers."Revenue growth has been steady across all geographies," chairman Sunil Bharti Mittal said in a statement, adding he expected "an exciting year of transformation."The company's shares plunged by more than 4.5 percent after the results on investor disappointment over the earnings before recovering to close down 1.2 percent at 426.75 rupees.Analysts had expected Bharti to post a 15-billion-rupee profit for the three month period to June.But interest costs surged for loans taken for its acquisition of assets in Africa and the cost of financing its 156-billion-rupee purchase of faster third-generation mobile (3G) spectrum in India.Bharti, India's largest mobile firm by subscribers, paid $10.7 billion last June for the cash and debt of most of the Africa business of Kuwait telecom operator Zain, making the firm one of the top five global wireless players."The results were not very impressive," telecom analyst Shrishti Anand at Mumbai's Angel Broking told AFP."The investment in 3G will still take time to pay off," she said. "The only sweet spot for Bharti is Africa which is improving gradually but that will take time too."Bharti'a Africa unit showed a big drop in losses to 64 million rupees from 697 million rupees a year earlier while its revenues more than quadrupled to 43.78 billion rupees."All the needles are pointing in the right direction," Manoj Kholi, head of Bharti's Africa operations, told a conference call.But Bharti, which holds more than a fifth of India's market, is still struggling domestically, although the company said it was hoping for better times ahead with a potential end in sight to a savage tariff price war.Bharti has been embroiled in a vicious contest among the country's more than one dozen service providers that has driven tariffs to below one US cent a minute as mobile operators have pursued growth at the expense of profit.Average revenue per user -- a key barometer of profitability -- in India fell 12 percent from a year earlier.As a first sign of an end to the price wars in India, the world's fastest-growing cellular market and second largest after China, Bharti last month raised call charges for some pre-paid mobile schemes -- a move followed by rivals Idea Cellular and Vodafone."It is prudent for the market to be at sustainable levels of pricing," Sanjay Kapoor, chief executive of India and South Asia, told the conference call.The company also said there was still large growth to be tapped in India's rural heartland where 700 million people out of the country's population of 1.2 billion live.While the mobile market is saturated in India's urban centres, the number of telephones per 100 people in rural areas stands at 34.