A Nigerian diplomat was found dead in his home in the Sudanese capital Khartoum on Thursday, two security sources said.
They said police were investigating the incident but provided no details on how he died.
Officials from the Nigerian Embassy in Khartoum were not immediately available to comment.
Al-Arabiya channel identified the diplomat as the consul general and described his death as an "assassination". Reports on social media suggested the killers used a knife in the attack.
Though intermittent violence is common in the country's warring southern and western regions, violence in the capital is rare.
Sudan's President Omar Hassan al-Bashir has in recent months shaken up the security establishment, replacing the heads of the army and intelligence service in February.
Nigerian diplomat slaughtered in Sudanese capital Khartoum