SAO PAULO (Reuters) - Brazilian telecommunications operator Telefonica Brasil posted on Tuesday a net profit below analysts' expectations, even though it increased by 7.3% in the first quarter from a year earlier.

The firm, which is controlled by Spain's Telefonica, posted an 896 million real ($176.5 million) net profit for the quarter ended in March, while analysts polled by LSEG expected a 1.03 billion real net profit.

Its net operational revenue stood at 13.5 billion reais, rising 6.5% as its main mobile services business grew 9.3%.

Telefonica Brasil attributed the performance of its mobile unit to a 11.4% jump in post-paid revenues, as the company was able to expand its customer base and to increase its prices in the segment, while maintaining a record-low churn rate.

Earnings before interest, taxes, depreciation and amortization (EBITDA) increased 6.8% in the quarter to 5.28 billion reais, slightly below analysts' forecast of 5.35 billion reais.

EBITDA margin rose 0.1 percentage point year-on-year to 39%.

($1 = 5.0759 reais)