The leaked (Wiki) documents show the extent to which America was offering support to pro-democracy activists in Egypt while publicly praising Mr Mubarak (president) as an important ally in the Middle East.
The American Embassy in Cairo helped a young dissident attend a US-sponsored summit for activists in New York, while working to keep his identity secret from Egyptian state police.
On his return to Cairo in December 2008, the activist told US diplomats that an alliance of opposition groups had drawn up a plan to overthrow President Hosni Mubarak and install a democratic government in 2011.
He has already been arrested by Egyptian security in connection with the demonstrations and his identity is being protected by The Daily Telegraph.
The crisis in Egypt follows the toppling of Tunisian president Zine al-Abedine Ben Ali, who fled the country after widespread protests forced him from office.