Ghana's President John Mahama on Thursday doubled down on his call for the African Union to address "escalating" anti-immigrant unrest in South Africa, which he said risked undermining African solidarity.

Two Ghanaians have petitioned the International Criminal Court to investigate "repeated xenophobic attacks" in South Africa, a move Pretoria has dismissed as "opportunistic."

South Africa, which has long drawn documented and undocumented African workers, has been rocked by weeks of protests and unrest targeting immigrants, who are accused of taking jobs and resources.

More than 160,000 foreign nationals have left the country and several have died over the past two months.

'African solidarity'

Ghana first pushed for the AU to debate the violence in May, with Mahama noting that AU Commission chairperson Mahmoud Ali Youssouf had acknowledged the "urgent need" to table it for discussion at the bloc's next summit due next year.

"Placing this on the AU agenda gives South Africa a formal, constructive platform to share its perspective, and together, as a continent, work toward a lasting solution," Mahama said in a social media post on Thursday.

On Wednesday, Mahama met the AU chief in Accra where he said "it doesn't appear that the South African authorities are responding to the magnitude that one would expect them to."

He said the AU should take an "interest" in the matter which "has the potential to wreck everything that we have worked for, African solidarity, African integration."

'Big source of concern'

South Africa's Foreign Minister Ronald Lamola, who was in Ghana earlier this week to meet Mahama, told reporters back home that the trip to Accra was to address "continuous deluge of criticism from Ghana."

He said both sides agreed that even when there is irregular migration, it should be dealt with "in a human way and not through people taking the law into their own hands, which is what we've seen now in the isolated incidences in our country."

Ghanaian media reported Youssouf as saying that violence was a "big source of concern" for the commission.

Ghana and Nigeria have been the most vocal in condemning the anti-immigrant violence.

ECOWAS backs Ghana's petition

A summit of the West African regional bloc, ECOWAS, at the weekend backed Ghana's push for an AU debate "to seek a permanent solution."

Global conflict tracker ACLED's Susanna Deetlefs said the "nature" of the demonstrations in South Africa "has become more intense", adding that "more than 30 percent of demonstrations in July turned violent."