Apple Inc.’s Chief Executive Officer Tim Cook promised to keep investing in China during a meeting with Beijing’s top technology official, underscoring the country’s vital role in the iPhone maker’s global operations.

This is Cook's second trip this year to the world's biggest smartphone market where, in recent quarters, the iPhone maker has been losing market share to domestic rivals.

China is Apple's most important market outside the US. Recently, sales have been dropping as domestic producers gain market share.