According to most 'ulama' [1], though open tahaddi (challenge), that is, saying, "Go ahead and do the same! But you can't!" is not a condition for a mu'jiza (miracle), the meaning of a mu'jiza contains tahaddi. Because a tahaddi is not a matter of question in the reports made about the states of the Rising Day and future events, these are not mu'jizas against disbelievers. Believers believe that these reports are mu'jizas. The karamats [2] of Awliya' [3] are not mu'jizas because they do not claim prophethood and because there is no tahaddi in them.

[1] 'ulama': pl. of 'alim; 'ulama' ar-rasihin, those learned in both zahiri and batini sciences.
[2] karamat: pl. of karama.
[3] awliya: (pl. of Wali) a person loved by Allahu ta'ala.