China Petroleum and Chemical Corporation (Sinopec), the country's largest oil refiner, said late Thursday its net profit for the third quarter rose 3 percent from a year earlier.

Sinopec reported a net profit in the third quarter of 20.22 billion yuan (about 3.18 billion U.S. dollars), up 19.63 billion yuan from the same period last year.

The refiner attributed the growth to the strong output of refined oil and chemical products which offset refining losses caused by government-controlled retail oil prices.

Sinopec posted refinery output of 4.37 million barrels per day during the first three quarters, up 3.6 percent from a year earlier.

But its overall crude output dropped 3.6 percent in the first nine months to 239.56 million barrels as maintenance activity affected overseas production, which just resumed in the third quarter.

Natural gas production surged 22.1 percent to 10.82 billion cubic meters during the period, it said.

The figures were calculated based on international accounting standards, according to the company.

The Chinese government dropped retail fuel prices by about 3 percent earlier this month, which will cut into the profit margins of refiners.

Sinopec opened slightly higher at 7.18 yuan Friday, up 0.7 percent from Thursday, outperformed by the benchmark Shanghai Composite Index which opened up 1.09 percent.