The United States has invited the leaders of six of the biggest Iraqi opposition groups to Washington to discuss plans to remove President Saddam Hussein from power.

The talks next month are expected to focus on co-ordinating efforts towards the eventual removal of the Iraqi leader.

The invitation suggests President Bush's administration is now taking the view that Mr Saddam's Iraqi opponents should play a significant part in any military campaign to overthrow him.

Opposition sources said it was not clear if Washington was moving any closer to preparations for such a campaign.