Apple Inc. reported its fastest quarterly revenue growth in more than three years, easily topping Wall Street estimates, after demand picked up for the iPhone and products in China.

Apple's best revenue growth in three years failed to impress, with shares down about 1% in volatile trading on Friday, as investors questioned whether a tariff-driven surge in iPhone sales would last.

Apple reported strong iPhone sales and rebound in revenue from China, giving a much-needed boost to two parts of the company’s business that had struggled over the past year.