The West Ham United player has been fined for his actions and the Royal Society for the Prevention of Cruelty to Animals has launched an investigation into the matter.
Kyle Mullen, a 24-year-old, died after completing a 5 1/2-day assessment designed to test SEAL candidates' endurance and mental rigor. A second candidate is in stable condition, the Navy said.
Officials warn that an attack could result in the deaths of tens of thousands of soldiers and civilians, while millions of Ukrainian refugees would be left to flee, likely to nearby Poland.