In July, the group issued a statement condemning the "unmindful killings of Nigerians residing in and or visiting South Africa." And in August, it led protests at South African chain stores in Ogun state, Nigeria.
South Africa's international relations minister Naledi Pandor has denied the killings. "The protests are said to be in response to alleged killings of Nigerians by South Africans," she was quoted as saying. "As you are aware, these allegations are devoid of truth, reckless, and unwarranted."
Number of 800,000 seems 'absolutely inflated'
The tweet's figures are attributed to NAN, the state-run News Agency of Nigeria. A senior editor told Africa Check NAN had published the figure before and called it a "conservative estimate", though "no census or official figure has been released on the number of Nigerians in South Africa".
The most recent data on how many Nigerians (and other foreign-born migrants) live in South Africa can be found in Statistics South Africa's 2016 Community Survey. It estimated that 30,314 people, or about 2% of foreign-born people living in South Africa, were from Nigeria.
The 2011 census, the most recent, estimated there were 26,341 Nigerians living in South Africa that year.
"Whilst there were problems in the conducting and processing of the [2016 Community Survey] the number of Nigerians seems about correct in that survey," Diego Iturralde, executive manager of demography at Stats SA, told Africa Check. "There have been no further data collection exercises with regards to migrant origins and flows which could update this number."
Both the community survey and census showed that the Zimbabwean and Mozambican diaspora were the largest groups of migrants in South Africa. They accounted for about half of the foreign-born population, Iturralde said. "There is no reason for that to have changed."
Lorena Carrasco, associate professor in the sociology department at the University of the Witwatersrand, told Africa Check while it was impossible "to establish with certainty the number of Nigerians in South Africa, as well as to do so with any other nationality", the number of 800,000 seemed "absolutely inflated". - Cayley Clifford
UPDATE: This spot-check was updated with comment from NAN after publication.