The text of the message is as follows: 

In the Name of God

I express my sincere condolences to the bereaved families and relatives of the sailors who died after their oil tanker caught fire and sank in a bitter and heart-wrenching incident, which was truly catastrophic and saddening, and I beseech God Almighty to bring consolation and peace upon their sorrowful hearts. Those loved ones lost their lives in the line of duty and while serving their country, and this is a great honor which may alleviate the burden of this grief and console the hearts of those affected. I ask God Almighty for mercy and blessing [upon the souls] of them (the victims) and fortitude and reward for their survivors. 

Seyyed Ali Khamenei 
January 14, 2018