Apple's exclusivity deal with AT&T in the US may have infuriated some who were eager to try out iPhone on rival networks, but the timely launch of the handset on Verizon now appears to be a mini-masterstroke.

Just as Android appears to be gaining the upper hand in North America, the NPD Group reports strong sales of Verizon's iPhone 4 have helped push Apple into third spot in the US.

The body's latest mobile phone track claims iPhone now has a 14 percent share of the mobile market, with the device holding its position as the top selling mobile across the country.

Top of the table

Samsung remains top dog, however, with a 23 percent share of the market. LG holds second position, accounting for 18 percent of the market.

"Apple and Verizon had a very successful launch of the iPhone 4, which allowed the iPhone to expand its market share that was previously held back by its prolonged carrier exclusivity with AT&T," said executive director of industry analysis at NPD, Ross Rubin.

"While some of that growth came at the expense of Android operating system, Android models still accounted for half of all smartphones sold in the quarter."

Ailing Android

Indeed, NPD reports that Android lost ground in the US for the first time since Q2 2009, down to 50 percent of all smartphone sales from a 53 percent share the previous quarter.

Apple accounts for 28 percent of all smartphone sales, ahead of BlackBerry, which fell by 5 percentage points to 14 percent.

"The rise of Apple and HTC show how companies can drive change in a mature device market to change the rules of the game," added Rubin.

"The overall success of US market leaders Samsung and LG will be tied to their success in the smartphone market."

In total, NPD claims smartphone units sales were up 8 percent in Q1 2011 compared to the previous quarter, though overall handset sets fell 1 percent.

[source: NPD]