Current Millwall and Montenegro goalkeeper Matija Sarkic died on Saturday at the age of 26, the Championship club confirmed.
Sarkic fell ill in his home country while on international duty. Montenegrin daily newspaper Vijesti reported Sarkic died in an apartment in Budva early in the morning.
"Everyone at the club sends their love and condolences to Matija's family and friends at this immensely sad time," the Championship club said in a statement.
"The club will make no further comment at this time and asks that the privacy of Matija's family is respected."
Sarkic made nine saves in Montenegro's 2-0 defeat to Belgium in a friendly last Wednesday and was named man of the match for his outstanding performance.
Born in Grimsby, England, Sarkic played for Aston Villa and Belgian side Anderlecht at youth level. He made 33 appearances for Millwall since joining in August 2023 from Premier League side Wolverhampton Wanderers.

Bayern, Arsenal win in Champions League quarter final first-legs
Former Romania football coach Lucescu dies aged 80
McIlroy says Augusta burden gone after Masters triumph
UAE Team Emirates rider achieves third on Itzulia Basque Country opening day
Pogacar wins third Flanders crown but faces fine for running red light
