Symbian reported Thursday that shipments of smartphones using its eponymous operating system have topped the 100 million mark, with Symbian-equipped handsets in the hands of customers of more than 250 network operators worldwide.

Symbian OS handsets are riding the wave of smartphone growth that has been building in recent months. Some 13 million Symbian smartphones were shipped in the third quarter, recording a 52% gain over the 8.5 million units shipped in the year earlier quarter.

The gains were recorded across the globe as new Symbian handsets with improved capability and lower prices were introduced.

"We see two trends driving smartphones onward," Nigel Clifford, Symbian's CEO, said in a statement. "The first is that while smartphones have their highest penetration rates in the most saturated and developed markets, the highest future growth rates are likely to be in rapidly developing markets such as China, India, and Brazil. The developing world will likely account for 50% of smartphone sales within five years."

In adiditon, the youth market represents a rapid growth opportunity for Symbian OS phones.

Symbian phones have been taking off in the U.S. in recent months and in past weeks have received a boost from the introduction of the Nokia E62 phone by Cingular Wireless, according to a spokeswoman for Symbian. The device, which features a QWERTY keyboard, is available from Cingular for $99 with a two-year contract.

Cingular's Symbian Zone on Cingular devCentral also has helped accelerate the move to the operating system as developers can access the Symbian OS Library for Application Developers to work on phones based on Symbian OS v9. Nearly 800 software titles are available for downloading to Symbian smartphones through Handango. The titles range from business and communications apps to games and personal finance.

Nokia owns the largest piece of Symbian, with Ericsson, Sony Ericsson, Panasonic Mobile Communicaitons, Siemens, and Samsung Electronics accounting for lesser percentages of equity ownership. Other handset manufacturers lease the technology from Symbian.

Additional handset makers offering Symbian OS devices include BenQ, Ericsson, Fujitsu, Lenovo, Mitsubishi, Motorola, Panasonic, Samsung, Sendo, Sharp, Siemens, and Sony Ericsson.

In addition to the Nokia E62 in the U.S., other recent models introduced globally include the Nokia 5500 Sport and SEMC P990 in Europe, as well as several NTT DoCoMo devices in Japan.