Nigeria will repatriate 130 of its nationals living in South Africa after a fresh wave of anti-immigration protests, Foreign Minister Bianca Odumegwu-Ojukwu said Monday, as she summoned South Africa’s top diplomat in Abuja to convey “profound concern” over the safety of Nigerian citizens.

The repatriation is voluntary and more people are expected to sign up, Odumegwu-Ojukwu said. She stressed that no Nigerians were killed in the protests themselves.

Two Nigerians, however, died last month in separate incidents involving South African security forces, according to a spokesman for Nigeria’s foreign ministry. Nigeria has requested an investigation into those deaths and is seeking cooperation in providing autopsy reports for the families of the deceased.

South African officials have condemned the violence and promised to crack down on “xenophobic acts.” Foreign Minister Ronald Lamola said he spoke by phone with his Nigerian counterpart to reflect on the “challenges posed by irregular migration” and to work on addressing root causes and finding solutions.

Anti-immigrant sentiment has flared periodically in South Africa, where high unemployment has fueled accusations that migrants take jobs from locals. Nigerian citizens have been targeted in past waves of violence, prompting periodic repatriation efforts.