The South African police have refuted claims that the Nigerian man who lost his life in their custody was a victim of xenophobia.

The Nigerian government deduced that the South African police were criminally liable, and warned that it would deploy regional and international measures to hold those guilty for violence against foreign citizens accountable.

Nigeria accused South African police, particularly Tshwane Metro Police personnel, of killing a Nigerian on June 28 in Pretoria "using gruesome interrogation techniques," according to an emailed statement from the Nigerian foreign ministry on Sunday.

However, in a response on Tuesday, the South African law enforcement agency noted that the victim collapsed after being arrested for drug use and not xenophobic attacks.

"The South African ​Police Service strongly rejects attempts to link this incident ​to anti-illegal immigrant protests," a police spokesperson said in a statement.