Google's dominance of the smartphone market has reached new heights, with its Android operating system now accounting for a record 84.6% share of global smartphone shipments, according to research by Strategy Analytics.

The growth in Android phones during the second quarter of this year came at the expense of BlackBerry, Apple iOS and Microsoft's Windows Phone, the research firm said Wednesday.

Android accounted for 249.6 million smartphones shipped in the quarter, up from 186.8 million a year earlier, and about seven times more than the 35.2 million Apple iOS phones shipped. The market share of Apple's iOS slipped to 11.9% in the quarter from 13.4% in the same quarter last year.

"Android's global growth is being driven by strong demand for low-cost smartphones across most major regions such as China, India and Africa," Neil Mawston, Strategy Analytics' executive director, wrote in an email. "The main threat to Android's future growth is Apple's upcoming portfolio of larger-screen iPhones during the next three to six months."

Millions of Android users worldwide will likely switch to the bigger-screen iPhones later this year, Mawston added.

Overall global smartphone shipments grew 27% annually in the quarter to 295.2 million units from 233 million a year earlier. While growth has slowed to its lowest level in five years, it remains strong in Asia and Africa and weaker in North America and Europe.

The latest shipments tally was in line with numbers released on Tuesday by IDC, which said top-ranked Samsung saw its market share slip to 25.2% in the quarter from 32.3% a year earlier.

Strategy Analytics said earlier this month that the number of smartphone users around the world will approach 2.5 billion by the end of 2015, fueled by strong growth in East Asia.