Nigerian and South African officials met in Abuja on Monday to address tensions over anti-migrant violence in South Africa, with both sides acknowledging their longstanding ties while clashing over Pretoria's handling of the attacks.

Nigeria accused South African authorities of failing to protect migrants, saying some Nigerians with legal residency had been assaulted while police looked on. 

"We could see some mob actions in which we saw the police watching, as if they are helpless to address this situation," Nigeria's junior minister for foreign affairs, Sola Enikanolaiye, said before the meeting went into a closed-door session.

The meeting came after weeks of anti-migrant protests in South Africa. More than 160,000 foreign nationals have left the country, including about 1,500 Nigerians.

South African police say at least four foreign nationals have been killed in attacks linked to the anti-migrant protests, though some African governments repatriating citizens have reported a higher toll.

South African Minister of International Relations and Cooperation Ronald Lamola said the government opposed xenophobia but defended its right to tackle irregular migration and crimes such as drug trafficking and fraud. The talks underscore growing regional concern over violence that has prompted sharp criticism from Nigeria and other African governments.