Apple sold 13 million iPhone 6s and iPhone 6s Plus in the past three days, breaking the company's own record for a launch weekend by more than three million phones.

"Sales for iPhone 6s and iPhone 6s Plus have been phenomenal, blowing past any previous first weekend sales results in Apple's history," Apple CEO TIm Cook said in a statement on Monday.

The sales figures include units from China, which is becoming an increasingly important market for the company.

But the smartphones are currently on a limited release: the device will be available in 40 more countries on Oct. 9, and in 130 countries by the end of the year, Apple says.

IPhones have revolutionized the smartphone space since their launch in 2007, growing to become the bestselling phone of all time, and changing Apple in the process. Formerly a computer company then a music device maker, iPhone sales currently make up about 60 per cent of Apple's revenues.

Apple shares are down about 15 per cent since the latest iPhones were announced, partly because of doubts the company can keep up it impressive sales growth rate while the Chinese economy is showing signs of slowing.

Apple didn't announce how many of the 13 million phones were sold in China.