Global sales of smartphones to end users totaled 349 million units in the first quarter of 2016, a 3.9% increase over the same period in 2015, according to Gartner. Samsung extended its lead over Apple with 23% market share, while Apple had its first double-digit on-year decline with iPhone sales down 14%.

"Samsung's Galaxy S7 series phones and renewed portfolio positioned it as a strong competitor in the smartphone market, and more so in the emerging markets where it has been facing fierce competition from local manufacturers," said Anshul Gupta, research director at Gartner.

Samsung's smartphone sales totaled 81.186 million units in the first quarter of 2016, up slightly from 81.122 million a year earlier, Gartner disclosed.

Apple saw its iPhone sales decline 14.2% on year to 51.629 units in the first quarter of 2016. The vendor's share of the global smartphone market slid to 14.8% from 17.9% in the first quarter of 2015, Gartner said.

"In a slowing smartphone market where large vendors are experiencing growth saturation, emerging brands are disrupting existing brands' long-standing business models to increase their share," Gupta continued. "With such changing smartphone market dynamics, Chinese brands are emerging as the new top global brands."

Gartner found that two China-based brands ranked within the top-5 worldwide smartphone vendors in the first quarter of 2015 and represented 11% of the market. In the first quarter of 2016, there were three China brands – Huawei, Oppo and Xiaomi – and they achieved 17% of the market.

Oppo among the top-5 smartphone vendors had the best performance in the first quarter of 2016, moving into the No. 4 position with unit sales growth of 145%. Like Huawei and Xiaomi, Oppo saw strong growth in China, taking share from players such as Lenovo, Samsung and Yulong, Gartner indicated.

Huawei saw strong smartphone demand in Europe, the Americas and Africa, while Xiaomi and Oppo saw their smartphone sales in emerging Asia/Pacific rise by 20% and 199%, respectively, Gartner noted.

Lenovo disappeared from the top-5 smartphone vendor ranking as well as the top-10 mobile phone vendor market in the first quarter of 2016, according to Gartner. "Lenovo had another challenging quarter with its worldwide smartphone sales declining 33%," said Gupta. "Its smartphone sales fell by 75% in Greater China, where it faced strong competition from local brands. Lenovo is also struggling to bring synergies with Motorola's device business, managing lower costs and overheads of the two brands."

In terms of the smartphone operating system (OS) market, Android regained share over iOS and Windows to achieve 84% share in the first quarter of 2016. "As mature smartphone markets are reaching saturation, Google is pursuing new revenue growth opportunities by expanding the reach of its platforms in cars, wearables, connected homes, immersive experiences and more," said Roberta Cozza, research director at Gartner.

Despite the Android platform's advancements and its dominant market share, the challenges of profitability remain for a number of Android players, Gartner said.

"Nokia's announced return to the smartphone and tablet markets will not be an easy mission," Gupta commented. "In today's market it takes much more than a well-known brand to sell devices. Making good hardware won't be an issue for Nokia, but users need a compelling reason to remain loyal to the same brand. Furthermore, that the smartphone market is slowing down makes it difficult for mobile phone vendors to reach previous levels of growth. New company HMD is entering the market at a less prosperous time, making it even more difficult for the vendor to do well in the short term."