Sani Kaita sees red for a foul on Vassillis Torosidis
Nigeria midfielder Sani Kaita has had more than 1,000 death threats since being sent off during Thursday's 2-1 loss to Greece at the World Cup.
"Kaita has received more than 1,000 threats to his e-mail from Nigeria," said team spokesman Peterside Idah.
"We are taking these threats very seriously. We've spoken to the Nigerian government and also written to Fifa."
Nigeria were leading 1-0 when Kaita saw red for kicking out at Greece's Vassillis Torosidis in the 33rd minute.
The Super Eagles went on to concede two goals, seriously damaging their chances of reaching the knockout stages in South Africa.
"We consider it a very serious matter because this is a young man who is putting his best at the service of his country and football," stated Idah.
"That is why the team received the news of the threat to his life with shock and disappointment and is urging the authorities in Nigeria to take measures to protect him."
Idah added that the 24-year-old midfielder was "terribly shaken, but, fortunately, he is receiving great support from his team-mates and team officials".
Nigeria take on South Korea at the Moses Mabhida stadium in Durban on Tuesday and must win to stand any chance of qualifying for the last 16.