WRAPUP 1-Mousavi rally in doubt after Iran leader warning

* Mousavi not calling for Saturday protest - ally

* Top legislative body to meet on vote complaints

* Karoubi wants election cancelled

* Khamenei speech draws Western criticism

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

By Dominic Evans and Fredrik Dahl

TEHRAN, June 20 (Reuters) - Backers of beaten presidential candidate Mirhossein Mousavi will decide on Saturday whether to defy a stern warning by Iran's top authority and stage mass protests over a disputed election.

Iran's top legislative body holds an extraordinary session on Saturday morning to which it has invited Mousavi and the two other candidates who lost against President Mahmoud Ahmadinejad in the June 12 election, which Mousavi wants annulled.