Matija Sarkic, Millwall's goalkeeper, has died aged 26.

Sarkic fell ill while on foreign service for Montenegro.

On Saturday morning, while with friends at an apartment in Budva, Montenegro, he suddenly became unwell.

Despite being swiftly transported from the scene by EMS, he died approximately 6:30 a.m. local time.

Local police have launched an investigation into Sarkic's death, albeit it is believed to be the result of natural causes.

Millwall, the Championship side, announced in a statement that they were devastated by the news and have blackened off their X profile out of respect.