However, almost all grand Ayatollahs of Shia prohibited these type of mourning. For example, Imam Khamenei, about 20 years ago said:
Tatbir is one of the wrong doings. I know some will say: “It would have been proper if he had not talked about Tatbir.” They will say: “What do you have to do with Tatbir? Some people practice it, let them do so!” No! One cannot remain silent towards such a wrong action.
It is wrong that some people hold daggers and hit themselves on the head to bleed. What are they seeking?! How can this be an act of mourning?! Of course hitting on the head with one’s hands is a sign of mourning. You have seen it several times that when people face suffering, they hit on their chests and heads. This is a typical symbol of mourning. But where have you ever seen a person who is suffering from the loss of a dear one, hit on their head with a dagger and make it bleed?! How can this be a form of mourning?
#Tatbir [#QameZani] is a fabricated tradition. It is among the issues that does not belong to the religion and undoubtedly God is not also pleased with such a practice.
The more I thought about it, the more truly I realized I cannot overlook informing our dear people about Tatbir- which is certainly an act of wrongdoing and a heresy. Do not practice it! I do not approve of it. If someone does something to pretend that they want to practice Tatbir, I will be truly dissatisfied with them. I am declaring this solemnly.
Ayatollah #Khamenei, June 07, 1994
This act, that is well-supported by Western news channels like BBC, CNN and others, is also prohibited in Quran:
And spend in the way of Allah and do not throw [yourselves] with your [own] hands into destruction. And do good; indeed, Allah loves the doers of good.