What is the ruling on bank prizes in Iran, given its claim to implement an Islamic economic system, and what should a Muslim do if he wins one through a lottery?

If prizes are obtained as a result of dealing with a bank through current accounts, savings accounts, or speculative investments, then these prizes are not permissible, even if the bank is Islamic. The winner must return the prize to the bank if it is Islamic. However, if it is not Islamic, the winner should spend it on matters benefiting Muslims, such as the poor and needy, and building hospitals and schools.