EDITOR'S NOTE: Iranian authorities have barred journalists for international news organizations from reporting on the streets and ordered them to stay in their offices. This report is based on the accounts of witnesses reached in Iran and official statements carried on Iranian media. ___ Supporters of President Mahmoud Ahmadinejad celebrated Tuesday after Iran's highest electoral authority proclaimed the validity of its disputed election, paving the way for the incumbent to begin a second term despite claims of fraud. Pro-Ahmadinejad newspapers announced the Guardian Council's approval in large type on their front pages.