WRAPUP 1-Iran set for day of mourning after protest deaths

* Mousavi calls for peaceful demonstrations

* Reformist clerics seek permission for rally

* U.S. rejects "meddling" accusation

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 and Hashem Kalantari

TEHRAN, June 18 (Reuters) - Supporters of Iran's defeated presidential candidate Mirhossein Mousavi prepared to heed his rallying call for a national day of mourning on Thursday for those killed in post-election clashes.

State media said seven people were killed in an opposition protest in Tehran against what Mousavi says was a rigged election last week in favour of hardline incumbent President Mahmoud Ahmadinejad.