WASHINGTON -- Smartphones using the Android platform boosted their U.S. market share in recent months, extending their lead over Apple's iPhone (IW 500/9), a new survey shows.

Android, the free mobile operating system from Google, accounted for 51.2% of U.S. smartphone sales in the three-month period ending in February, said the survey from Kantar Worldpanel ComTech.

Android added 5.9 percentage points from a year earlier, while Apple's share fell 3.5 points to 43.5%.

Windows Phone, boosted by the new operating system introduced last year from Microsoft (IW 500/15), increased its share to 4.1%, according to the survey released Monday.

BlackBerry, which introduced a new smartphone platform in late January but started selling its new phones in the U.S. market only in late March, saw its market share tumbled to just 0.7%, the report showed.

Verizon was the top carrier with 35% of smartphones sold in the period, followed by AT&T (26.7%) and Sprint (15%).

Kantar analyst Mary-Ann Parlato said Samsung (IW 1000/25), the largest Android smartphone maker, has been continuing to rise, particularly among Sprint customers.

"Of those who changed their phone over the last year to a Samsung smartphone, 19% had previously owned a Samsung featurephone, 15% owned a HTC smartphone, 14% owned an LG featurephone, 10% owned a Samsung smartphone and 9% owned a BlackBerry," she said.

"It's apparent that Samsung is successful at capturing users from across the competitor set and not just gaining from their own loyalists."

Copyright Agence France-Presse, 2013