If paid my property taxes for 2016 in Jan 2017. Am I allowed to deduct that on my 2017 returns ? or is it only in the year which it is for ?

I paid my property taxes for 2016 in Jan 2017. Am I allowed to deduct that on my 2017 returns ? 

Also if I paid the 2017 taxes before December 31, 2017, then can I include both payments ?