Google's Android mobile operating system surged past Apple's iPhone and Canada's Blackberry in the third quarter to become the second biggest smartphone platform after Nokia's Symbian, research firm Gartner said Wednesday.

Gartner said Finland's Nokia sold 29.5 million smartphones during the third quarter of the year for a 36.6 percent share of the worldwide market, down from 44.6 percent a year ago.

Sales of Android-powered smartphones soared to 20.5 million units, giving the Android platform a 25.5 percent market share, up from just 3.5 percent a year ago, Gartner said.

Apple's iPhone was next on sales of 13.5 million units for a 16.7 percent market share, down from 17.1 percent a year ago.

Canada's Research In Motion, maker of the Blackberry, was in fourth position with sales of 11.9 million units. Its market share dropped to 14.8 percent from 20.7 percent a year ago.

Microsoft's Windows Mobile saw sales of 2.2 million units giving it a 2.8 percent market share, down from 7.9 percent a year ago, Gartner said.

"Smartphone (operating system) providers have entered a period of accelerated platform evolution, stimulated by more regular product releases, new platform entrants and new device types," said Roberta Cozza, principal research analyst at Gartner.

"Any platform that fails to innovate quickly -- either through a vibrant multi-player ecosystem or clear vision of a single controlling entity -- will lose developers, manufacturers, potential partners and ultimately users."

Gartner said worldwide mobile phone sales totaled 417 million units in the third quarter, up 35 percent from a year ago.

Smartphone sales grew 96 percent to 81 million units and accounted for 19.3 percent of overall mobile phone sales in the quarter.

Nokia remained the world's top handset manufacturer with sales of 117.5 million units in the third quarter but saw its worldwide market share slip to 28.2 percent from 36.7 percent a year ago.

South Korea's Samsung was next on sales of 71.7 million units but its market share also fell -- to 17.2 percent from 19.6 percent a year ago.

South Korea's LG sold 27.5 million handsets. Its market share dipped to 6.6 percent from 10.3 percent a year ago.

Apple leapfrogged RIM during the quarter with sales of 13.5 million units, giving it a 3.2 percent market share, up from 2.3 percent a year ago.

RIM sold 11.9 million units. Its market share edged up to 2.9 percent from 2.8 percent a year ago.

Sony Ericsson sold 10.3 million units for a 2.5 percent market share, down from 4.5 percent, while US handset maker Motorola sold 9.0 million units for a 2.1 percent market share, down from 4.5 percent a year ago.

Gartner said Samsung was the top Android seller in the quarter with sales of 6.6 million Android phones.

The technology research company said it expects overall mobile device sales to grow 30 percent year-on-year in 2010 and for sales of tablet computers such as Apple's iPad to reach 54.8 million units in 2011.