WRAPUP 1-Thousands mourn Iranians killed in protests

* Supreme leader to address Friday prayers

* Guardian Council invites losers to discuss complaints

* Iran says thwarted election day bomb plot

EDITORS' NOTE: Reuters and other foreign media are subject to Iranian restrictions on their ability to report, film or take pictures in Tehran.

By Parisa Hafezi

TEHRAN, June 19 (Reuters) - Iran's supreme leader will address the nation on Friday for the first time since a disputed election result triggered the biggest protests the Islamic Republic has seen.

Ayatollah Ali Khamenei has urged Iranians to unite behind hardline President Mahmoud Ahmadinejad but supporters of defeated candidate Mirhossein Mousavi have so far ignored the call, holding huge rallies in defiance of an official ban.