Apple unveils refreshed iPhone 4S, but no iPhone 5

The iPhone 4S, as the model will be known, boasts an improved camera and significantly extended battery life.

It will run the latest iOS5 operating system, which is set for release on 12 October.

The event was the first major announcement for new boss Tim Cook who took over from Steve Jobs in August.

The iPhone 4S, which will go on sale on 14 October, will be available in 16GB, 32GB and 64GB models - in both black and white.

It has the same look and feel as the existing iPhone 4 which was launched 15 months ago.

However, Apple said that updates to iOS meant the phone would boast some "200 new features".

Shares in Apple fell by almost 5% within minutes of the eagerly anticipated launch, with analysts saying that investors and Apple fans had expected the latest version to be a more radical improvement over its predecessor.

However, the company's shares later regained most of their losses to close down just 0.6%, albeit underperforming the NASDAQ index as a whole.

Among the additions is an "intelligent assistant" that allows users to ask questions aloud and receive detailed answers back.

Siri, which began life as a third-party app, was purchased by Apple in 2010 but has yet to appear within its software.

Luke Peters, editor of gadget magazine T3, said that the software announcements would do just enough to keep Apple fans interested in the face of strong challenges from rival smartphone manufacturers.

Other industry watchers were less charitable about the iPhone refresh, and the non-appearance of the iPhone 5.

Gareth Beavis, phones editor at TechRadar said that the new hardware would leave many people underwhelmed.

"It was quite disappointing. I think there is going to be a lot of anger from users expecting something big bold and quite exciting after a long time of waiting from the iPhone 4.

"People will buy this in their droves, but Apple has missed a trick by just releasing the exact same phone again with marginally upgraded specs."

Details of the new phone were unveiled by Apple's Philip Schiller

For Apple's new chief executive, the event was as much about making a statement about his leadership as it was new products.

Tim Cook had previously acted as interim boss, looking after the company while Steve Jobs was on sick leave.

Unlike his charismatic predecessor, Cook left the biggest announcement of Tuesday's event to a colleague - marketing boss Phil Schiller.