Nigeria said it would boycott the World Economic Forum hosted in Cape Town on Wednesday over a wave of anti-migrant attacks in South Africa, as diplomatic tensions deepened between Africa's biggest economies.
The move comes as South Africa and Nigeria stepped security after deadly attacks on foreign-owned stores in Johannesburg that have triggered reprisal assaults on South African businesses in Nigerian cities.
"Nigerian government has boycotted the World Economic Forum being held in Cape Town, South Africa," an advisor to President Muhammadu Buhari, Bashir Ahmad said on Twitter, although he said some individuals would attend independently.
Nigeria's Vice President Yemi Osinbajo had been expected to attend the annual summit of leaders and business figures, but cancelled his trip, a day after Africa's most populous country summoned the South African ambassador for talks.
In Nigeria, police on Wednesday said security had been strengthened around South African businesses after apparent reprisal attacks in several cities against stores operated by the supermarket chain Shoprite, the telecoms giant MTN and other firms.
But in the capital Abuja, scores of demonstrators clashed with police outside a shopping mall which has a Shoprite store.
On Monday and Tuesday, mobs descended on business hubs and townships in various parts of South Africa, looting dozens of shops and torching trucks driven by foreigners in an outburst of anti-migrant anger.
Five people, most of them South Africans, have been killed and almost 300 arrested.
South Africa is a major destination for economic migrants from neighbouring Lesotho, Mozambique and Zimbabwe. But others come from much farther away, including South Asia and Nigeria.
Foreigners in the country have been accused of taking jobs away from South Africans—nearly one South African worker in three is unemployed.
The violence has concern for relations between South Africa and its neighbours and Nigeria—the continent's most populous market.
Nigeria said on Tuesday that President Muhammadu Buhari was sending an envoy to convey his displeasure to South African President Cyril Ramaphosa.
South Africa has huge investments in Nigeria, with Shoprite, MTN, digital pay-television Multichoice and other companies jostling for a share of its market.
Information Minister Lai Mohammed also warned in a statement that "targeting South African companies in Nigeria for attack was akin to cutting off ones nose to spite the face."
"The investors in such companies, especially MTN and Shoprite, are Nigerians," he pointed out.
Nigerian celebrities have taken to social media in outrage, with music star Burna Boy leading calls for a boycott of South Africa while fellow stars Teni the Entertainer and Davido condemned the violence.