Hajj
Participation in Mass Prayers of Sunni Brothers
perform the circumambulation rite ordinarily, as all the pilgrims do. Avoid what the ignorant ones do and what many disgrace the religion absolutely.
During VOQUFEIN, observance of the decrees of the Sunni judges is necessary and allowed, even if deemed inappropriate.
It is necessary that our Iranian brothers as well as Shias of all other countries avoid any unwise actions that may create a schism within the muslim lines. They are required to join the Sunni brothers' mass prayers. They should also avoid convening mass prayers inside their houses, and utilizing loud speakers inordinately, and they must abstain from throwing themselves on the holy tombs, or doing things that are sometimes against canon law.
Source:
"Hajj In The Words and Messages of Imam Khomeini" book
Other Links:
HAJJ : IMPORTANT WORSHIP FOR HUMAN DEVELOPMENT
Hajj: The Necessity of Carefull Learning of the Hajj Rituals