There is a mosque containing graves, and people have prayed in it for a period of time, then they became aware of this. What is the ruling?

Question:
I ask Allah to do you good, Your Eminence, father. The questioner says: There is a mosque with graves inside it, and people have been praying in it for a while. Then they found out and wondered. What is the ruling on their prayers during the past days? What should they do now? And what is obligatory upon them?

Answer:
They should remove the graves if the graves are newly established in the mosque and the mosque is old. The graves are to be dug up and buried in the public cemetery. However, if the situation is the reverse, meaning the graves are old and the mosque was built on top of them, then the mosque is to be demolished, the graves are to remain, and they are to be walled off and preserved. As for the many prayers that have passed while they were unaware, they are excused, if Allah wills. But it is necessary to clear the mosque of the graves, or to demolish the mosque if it is the later construction, and to build a replacement mosque that is free of graves. Yes.