Nigeria has summoned South Africa's acting High Commissioner over a spate of recent attacks on foreigners in the southern African nation.

Nigeria will formally convey its "profound concern" at a meeting on Monday over incidents in South Africa, saying they could affect existing relations between the countries, according to a foreign ministry statement.

The meeting will focus on recent marches held by anti-immigrant groups and "documented instances of mistreatment of Nigerian citizens and attacks on their businesses", it said.

At least two Nigerians and four Ethiopians have been killed in recent weeks, local media reported, while there have been attacks on citizens of other African countries.

As Africa's most industrialised country, people from elsewhere in the continent have long travelled to South Africa to seek work.

South African President Cyril Ramaphosa has condemned the attacks but also cautioned foreigners to respect local laws.

He used his Freedom Day address last week - marking the country's first democratic elections in 1994 - to remind South Africans of the support other African nations had given in the struggle against the racist system of apartheid.

But some South Africans accuse foreigners of being in the country illegally, taking jobs from locals and having links to crime, especially drug trafficking.

Anti-immigrant groups have been stopping people outside hospitals and schools, demanding to see their identity papers.

During a march by one such group in the capital, Pretoria, last week, foreign-owned businesses were urged to close in case of violence.

At the time, one Nigerian man told BBC Pidgin: "It is not okay because we are blacks, we are brothers... everybody comes here just to survive."

A security guard, who was unable to go to work because of the protest, told the BBC: "It's not what we expected as fellow Africans."

"It's just making us scared - imagine if we're scared in our own African continent - what if we go to Europe?" he asked.

Last month, Ghana summoned South Africa's top envoy after a video was widely shared showing a Ghanaian man being challenged to prove he had the correct immigration papers.

Anti-immigrant sentiment rose earlier this year after reports that the head of the Nigerian community in the port city of KuGompo (formerly East London) had been installed in a traditional role that can be translated as "king". Some South Africans in the local area saw this as an attempt to grab political power.

South Africa is home to about 2.4 million migrants, just less than 4% of the population, according to official figures. However, many more are thought to be in the country unofficially.

Most come from neighbouring countries such as Lesotho, Zimbabwe and Mozambique, which have a history of providing migrant labour to their wealthy neighbour. A smaller number come from Nigeria.