Nokia sold 5.6 million Lumia smartphones during the first quarter, up 27 percent from the previous quarter, the phone maker announced today.

Approximately two-thirds of those Lumia sales were for smartphones running Microsoft’s latest Windows Phone 8 platform, Nokia chief Stephen Elop said during a Thursday conference call.

“We are seeing our Lumia momentum accelerate as we exit Q1,” Elop said. As a result, Lumia growth in the second quarter will likely exceed the 27 percent it saw in the first quarter, he said.

Nokia sold 4.4 million Windows Phone-based Lumia smartphones in the fourth quarter of 2012, and 2.9 million in the months before.

Still, overall mobile phones sales had a “difficult” quarter, Elop said. Sales were down 30 percent quarter over quarter to 55.8 million units, “reflecting competitive industry dynamics,” Nokia said.

That competition is coming primarily from Apple’s iPhone and Samsung’s Galaxy lineup, as more and more people shift to smartphones. During the fourth quarter, Apple sold 47.8 million iPhones, while Samsung sold(Opens in a new window) 63 million smartphones. Apple will announce its first quarter results on April 23 and Samsung will report on April 26.

Elop, however, argued that the “Android experience is becoming inconsistent,” pointing to continued fragmentation and forking. “We are seeing leading tech companies take deliberate steps to change Android and possibly change our industry,” he said.

Elop also promised a “season of new product introductions” later this year. According to the Financial Times(Opens in a new window), new products will include a Lumia phablet, as well as a smartphone with Nokia’s Pureview imaging technology.

During the quarter, the red Lumia 822 was released on Verizon, while it was announced that the Lumia 521 is coming to T-Mobile next month. We also got a glimpse of the Lumia 520 (above) and 720 at Mobile World Congress.

Earlier this month, Kantar Worldpanel found that Microsoft’s mobile operating system had 4.1 percent of the U.S. smartphone sales for the three months ending in February, up from 2.7 percent during the same time period last year. The popularity of Nokia’s Lumia 920 helped push the Windows Phone along, Kantar said.

Those who try Windows Phone tend to love it; it came out on top for mobile OSes in PCMag’s recent Readers’ Choice survey. But it can be difficult to tear people away from their iPhone or Android device, particularly because of the lack of apps on Windows Phone compared to iOS and Android.