WRAPUP 10-Iran's Mousavi urges more protests, gunfire heard

* Mousavi urges more protests

* Gunfire heard in northern Tehran

* Clerics criticise leadership's handling of protests

* Authorities blame "terrorists" for unrest, 10 dead

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

(Updates UK think-tank's election analysis)

By Parisa Hafezi and Fredrik Dahl

TEHRAN, June 21 (Reuters) - Iranian opposition leader Mirhossein Mousavi urged supporters on Sunday to continue protests over a disputed presidential election, in a direct challenge to the leadership of the Islamic Republic.