Slovenia and Slovakia sound too similar for FIFA officials who got the two countries confused before a press conference on Tuesday, dpa reported.
The press conference ahead of England's game with Slovenia was billed as England v Slovakia. A Slovenian journalist complained to officials that it was not the first time the mistake had been made.
"We made a mistake and for that we apologise" said a FIFA spokesman. Slovenia face England in Group C while Slovakia face Italy on Thursday in Group F.