Google is delaying the rollout of its mobile phone handsets until the end of the year.

The firm was planning to ship mobile phones based on its Android software in 2008. The Wall Street Journal reported that carriers were reporting problems meeting the schedule set by Google.

The paper said that Android had not won support from large mobile-software developers. It said sources reported issues including difficulty developing programs while Google makes changes as it finishes its own software.

The firm has deals with China Telecom, T-mobile and Deutsche Telekom.