*** HOLD FOR EMBARGO MONDAY, FEB. 24 2100CET *** An employee displays a Galaxy S5 smartphone, left, and new Samsung Gear, center, and Gear Fit wristwatch devices during a Samsung Electronics Co. news conference ahead of the Mobile World Congress in Barcelona, Spain, on Sunday, Feb. 23, 2014. Top telecommunication managers will rub shoulders in Barcelona next week at the Mobile World Congress, Monday, Feb. 24 - 27, a traditional venue for showcasing the latest products for dealmaking. Photographer: Angel Navarette/Bloomberg

Barcelona - Samsung unveiled on Monday its new flagship Galaxy S5 smartphone armed with a fingerprint scanner and a built-in heart rate sensor to defend its place as the industry leader.

Taking the limelight on the opening day of the world’s biggest mobile fair in Barcelona, Spain, the firm simultaneously revealed a connected bracelet for health-concerned customers.

Samsung made about 30 percent of all smartphones sold in the world last year, nearly twice the share of arch-rival Apple.

But Samsung, which announced its new devices on the sidelines of the four-day event, is nevertheless scrambling for new revenue sources as competition in mature markets intensifies.

In a struggle to stand out from the competition, including a rising challenge from China, Samsung showed off the Galaxy S5 with a light sensor on the back that gives a heart rate reading when the user touches it with a fingertip. Though the case is plastic, as with earlier versions of the Galaxy series of smartphones, it is water- and dust-proof.

The smartphone boasts a full high-definition 5.1-inch screen and, catching up with Apple, the home button doubles up as a fingerprint reader to unlock the device or manage applications.

Global smartphone sales rose 42.3 percent to 968 million units last year, according to industry research group Gartner.

But the growth was powered almost entirely by developing markets, disguising a slowdown in mature markets such as Western Europe and the US, which are the most profitable. Samsung was one of the first smartphone makers to produce a smart watch when it launched the Gear last September. – Sapa-AFP