Toronto, May 11 (IANS) Though the Canadian icon BlackBerry continues to maintain its lead in the US smart phone market, handsets with Google's Android operating system may upset it soon, says a report released Monday.

In fact, the devices with the Google operating system have left Apple's iPhone behind in the first quarterly sales, says the report.

Prepared by the NPD Group, the US consumer market research company, the report says Google's Android operating system has shaken up the mobile phone market, moving past Apple to take the number two position among smartphone operating systems.

According to the report, the Android operating system is now at second position with a share of 28 percent, just behind BlackBerry's 36 percent. Apple's share is 21 percent.

"As in the past, carrier distribution and promotion have played a crucial role in determining smartphone market share,'' the report quoted NPD Group executive director Ross Rubin as saying.

Android's growth has been fuelled by aggressive marketing by the carrier Verizon Wireless. But Google's operating system still has a long way to go as it controls only 9 percent of the US market as against iPhone's 25.4 percent.

The US smart phone market is controlled by four carriers - AT&T (32 percent), Verizon Wireless (30 percent), T-Mobile (17 percent) and Sprint (15 percent).

"Carriers continue to offer attractive pricing for devices, but will need to present other data-plan options to attract more customers in the future,'' said Rubin.

The report comes just more than a month after Forbes said in March that BlackBerry's lead over iPhone is shrinking and it will overtake the Canadian icon by early next year.

Forbes had also said that the "end of AT&T exclusivity will give Apple's iPhone wider distribution in the US (comparable to BlackBerry distribution)."