Apple broke its sales record for an opening weekend of a new iPhone model, delivering 10 million in three days and boasting it could have sold more if it had them.

"Sales for iPhone 6 and iPhone 6 Plus exceeded our expectations for the launch weekend, and we couldn't be happier," Apple chief executive Tim Cook said Monday.

"We could have sold many more iPhones with greater supply and we are working hard to fill orders as quickly as possible."

The opening weekend for the large-screen iPhones allowed Apple to break its record for launch weekend sales of nine million, which its set last year when it launched the iPhone 5S and 5C.

The new models were launched on Friday in the United States, Britain, Australia, Canada, France, Germany, Hong Kong, Japan, Puerto Rico and Singapore.

They will be available in more than 20 additional countries from September 26, and 115 countries by the end of the year.

The positive response was noted by analysts who said Apple is likely to get a lift from the new phones.

- Apple 'executed well' -

"Despite the supply chain constraints... Apple executed extremely well in the face of severe supply constraints," said Brian White at Cantor Fitzgerald in a note to clients.

"More important to us, we believe Apple is in the midst of a 'super cycle' that we expect will keep the stock heading in an upward trajectory."

Benjamin Reitzes at Barclays was also impressed by the sales figures and added that "the key here is that the figure could have been much higher -- which is obvious if you visited a store over the weekend."

Apple shares gained 0.15 percent Monday to $101.11.

The global rollout led to long lines outside Tokyo's flagship Apple store in glitzy Ginza, and in stores from Hong Kong to Paris to New York.

Cook personally kicked off sales of the iPhone 6, joining in "selfies" and shaking hands with customers Friday outside the company's store in Palo Alto, California, near his Silicon Valley home.

Both new iPhones have larger screens as Apple catches up with the "phablet" trend pioneered by competitors such as Samsung, which has had success with its Galaxy Note series.

The iPhone 6 has a screen of 4.7 inches and the 6 Plus is 5.5 inches, reflecting a growing preference for bigger displays, despite Apple's earlier vow to stick with the traditional size.

Main rival Samsung has long had a range of larger handsets, which are popular in Asia, and will soon release a new Galaxy Note 4.

Apple said more than four million pre-orders were received in the 24 hours after the sale was announced.

The new iPhones come with Apple steadily losing market share to low-cost Android devices from South Korean rival Samsung and others.

While Apple sold more than 35 million iPhones in the second quarter, its growth was slower than that of many rivals and its market share dipped to 11.7 percent, according to the research firm IDC.

Samsung led the global smartphone market in the quarter with sales of 74 million and a market share of 25 percent, according to IDC figures.

But the strongest growth in the past quarter came from Chinese manufacturers such as Huawei and Lenovo, which boosted their market share, notably in their home market.

Apple has not yet announced plans for sales of the iPhone 6 in China. State officials said last week the US firm still needs to obtain "a key network access license" before selling on the mainland.

Apple did get broader access to the Chinese market earlier this year when China Mobile, the country's biggest wireless provider, started selling iPhones, ending a six-year wait in a crucial market for the US technology giant.

Along with the new iPhone, Apple released an updated mobile operating system, iOS 8 with more features for fitness monitoring and home automation.

The company also plans to roll out its Apple Watch which links to the iPhone in 2015, and has announced the newer iPhones would be equipped for mobile payments in the US market.