Apple on Thursday reported profits rose on the back of strong iPhone sales in the past quarter, with the US tech giant set to begin selling its newest flagship handset seen as a key to its future.

Net profit rose 19 percent from a year ago to $10.7 billion in the fiscal fourth quarter to September 30, Apple said. Revenues were up 12 percent to $52.6 billion.

Release of the earnings figures pushed Apple shares up more than three percent to $173.55 and came as iPhone X models began hitting the market in some time zones.

Apple sold more iPhones, iPads and Mac computers than it did in the same quarter a year earlier, smartphones sales climbing by about a million units to 46.7 million in the three months winding up the California company's fiscal year, according to the earnings report

"We're happy to report a very strong finish to a great fiscal 2017, with record fourth quarter revenue, year-over-year growth for all our product categories, and our best quarter ever for services," Apple chief executive Tim Cook said in the release.

"We're looking forward to a great holiday season, and with the launch of iPhone X getting underway right now, we couldn't be more excited as we begin to deliver our vision for the future with this stunning device."

Apple closed out its fiscal year posting a profit of $48.35 billion, up 5.8 percent, on revenues of $229 billion, a rise of 6.3 percent.

- Ambitious goal -

With its new iPhone X launching Friday, Apple is setting the ambitious goal for itself of reinventing the smartphone as strives to fend off fierce competition from rivals, especially in China.

The iPhone is the main profit driver for Apple, accounting for more than half its revenues, and importantly is the cornerstone for the ecosystem of other devices and services.

The flagship handset marking the 10th anniversary of the first iPhone release, was set to hit stores Friday in some 50 markets around the world.

Apple upped the ante by boosting the starting price of the new handset to $999 for US customers, a price which will be higher in other markets and with extra options.

The lofty price tag has caused Apple to lose its shine in the eyes of some people in countries dealing with tough economic times and low incomes.

Apple shares have climbed with the approach of the launch date, seeing a jump this week after it said pre-orders for iPhone X are "off the charts."

Cook has described the iPhone X as the future of the smartphone, packed with technology including facial recognition, cordless charging and an edge-to-edge screen made of organic light-emitting diodes used in high-end televisions.

Analysts interviewed by AFP see signs of strong demand for iPhone X, perhaps fueled by the company's famously devoted fans who have shunned freshly released iPhone 8 models to wait for the 10th anniversary device.