Is it permissible to train in a place where a mosque is being built?

Question:
This questioner says: Your Eminence, Shaykh Abdul Aziz, peace be upon you and Allah’s mercy and blessings, and after that:
I am one of the trainers in a military college for the sport of karate, which is a sport of self-defense, and the college does not have a place designated for training. So, is it correct for me to conduct training in a place that is being built on the basis that it will be a mosque, but is not yet completed?

Answer:
As long as this training is beneficial in the path of Allah and in jihad against His enemies, there is no harm. The Prophet (peace and blessings be upon him) approved the Ethiopians, and they played in the mosque with shields and spears, moving around in the mosque with shields and spears.
So if the sport is used to aid in defending oneself, jihad against enemies, and warding off their evil, there is no harm in a mosque that has an open space and ample room, until another place is found where the play can take place, on the condition that this play does not cause harm to the mosque through destruction, urine, or the like.