What is the ruling on praying in a mosque built on land that contains remains, after extracting a portion of them and covering the rest with a layer of gravel, sand, and concrete?

It is not permissible to exhume graves as long as the bones of the deceased are present. It is also not permissible to build upon graves because they are a right of the deceased. Prayer is not permissible in a mosque built upon graves. If the graves are dilapidated and worn out, then it is permissible to build on their sites; otherwise, it is not permissible. The mosque must be removed, and the graves left as they are.