Samsung Electronics Co halted sales of its Galaxy Note 7 smartphones and asked consumers to stop using the ones they've already purchased, another blow to South Korea's largest company as it struggles with a crisis over exploding batteries. Shares plunged, cutting $17 billion from its market value.

Samsung has already recalled the Note 7 once and the latest move comes after customers reported that replacement phones were also catching fire. Samsung may be forced to scrap an entire generation of Note smartphones, one of its two most important phone lines, a severe setback in its competition with rivals like Apple Inc.

The crisis has left millions of premium smartphone buyers looking for an alternative. The obvious candidate is Apple's iPhone 7, but Google's slick new Pixel device could get a lift, too.