Japanese tech giant Sony saw its net profit more than triple in the April-to-June quarter, helped by strong sales of its PlayStation 4 games and camera sensors.

A painful reversal in fortunes for Samsung Electronics' smartphone business continued in the second quarter, the company confirmed on Thursday, adding to scepticism about its strategy to halt its sliding market share.

"We made a decision back to September not to disclose the shipments of the watch," Cook told investors on Tuesday.

Growth in the world's second largest economy, China, beat expectations in the second quarter, but it was still the weakest showing since the global financial crisis.

Doubts over the sales prospects of Samsung Electronics' new flagship smartphones are damping expectations of a rapid turnaround for the South Korean giant, even though profit likely continues to recover from last year's troughs.

Demand for semiconductors continued to weaken in the second quarter with some PC assemblers in Asia suggesting a decline in purchases of some parts of as much as 15-20% from the second quarter of 2014, according to a report from Wall Street analysts at Deutsche Bank.