"Longer term, we maintain our concerns regarding smartphone share in the face of new competition from the likes of RIM, Apple and HTC (High Tech Computer)," analyst Kulbinder Garcha at Credit Suisse said in a research note.
Gartner said global smartphone sales growth almost halved from the first quarter to 15.7 percent.
"The current economic environment continues to negatively impact the market, limiting consumer spending and replacement purchases in general," Cozza said, adding growth should pick up again in July through September.
"Wider availability of new touch smartphone models together with the global introduction of the iPhone 3G will help sales of smartphones return to stronger growth in the third quarter of 2008," Cozza said.
Apple's share of global smartphone sales fell to 2.8 percent from 5.3 percent in the first quarter of 2008 as it sold down inventories of first-generation iPhones before the launch of the iPhone 3G.
HTC sales more than doubled from a year ago to 1.3 million phones, lifting the company to No. 3 position from seventh place the previous quarter.
In smartphone operating systems, Symbian lost market share as the Japanese market declined and Mitsubishi exited the market. Symbian had 57 percent of the market in the second quarter, compared with 66 percent in the same period last year.
RIM had 17.4 percent of the market and Microsoft's Windows Mobile market share stood at 12 percent in the quarter.