Speaking at AllThingsD’s Dive Into Mobile conference on Monday, Mozilla CEO Gary Kovacs announced that the first Firefox OS smartphones will launch around June, Business Insider reported. The executive revealed that initial availability will be limited to emerging markets including Venezuela, Poland, Brazil, Portugal and Spain. The HTML5-based operating system will also be making its way to the United States, as Sprint has previously confirmed that it plans to launch a Firefox OS smartphone sometime next year. Kovacs noted that the delay is due to the company’s plan to build a desirable ecosystem before launching in the highly competitive U.S. market.