Apple's new iPhone 4 has been put on the market for the first time in five of the world's largest economies.

In Japan, hundreds of fans were waiting outside stores for the doors to open. Some had camped outside for days.

Japan's launch on Thursday happened first before other countries due to the time difference. The new iPhone 4 has a higher-quality screen, longer battery life, new video chat software and better gaming.

Apple says it has already sold 600 thousand phones, a record for a single day of pre-orders last week. That means it sold 7 of them per second. But, analysts say a supply shortage could hamper initial sales and hurt Apple when it faces new competitors.

The iPhone 4 will debut in the US, France, Germany and the UK later on Thursday.