US President Barack Obama called French President Nicolas Sarkozy and Russian President Dmitry Medvedev on Saturday, to reaffirm their commitment to a UN-backed plan that would ship most of Iran's uranium abroad for enrichment. The three presidents endorsed the proposal this week as a means of calming fears in the West that Iran is developing a nuclear weapon. Iran has not said whether it will comply. The Teheran government insists its nuclear program is aimed at generating power and not building a weapon. The White House said that Obama thanked Sarkozy and Medvedev for their help in addressing the issue and discussed the importance of implementing it soon.