JOHANNESBURG — South Africa has revoked its decision to withdraw from the International Criminal Court, citing in a letter submitted to the United Nations a recent court ruling that declared the withdrawal “unconstitutional and invalid.”
It was not clear, however, if the South African statement on Tuesday meant that the country had abandoned intentions to leave the international court, or if it was seeking another way to do so.
Two other African countries, Burundi and Gambia, had announced plans to leave the court despite intense international pressure to stay, although Gambia reversed its decision last month. Supporters of the court fear that such withdrawals — especially by South Africa, one of the court’s staunchest early supporters — would lead to an African exodus from the tribunal.
The South African government of President Jacob Zuma has long criticized the international court as being biased against African states and, in its most recent public statements, the leadership has maintained its aim to leave the organization.
In the letter submitted on Tuesday to António Guterres, the United Nations secretary-general, South Africa joined Gambia in pulling back from plans to leave the court, saying that the “instrument of withdrawal was found to be unconstitutional and invalid.”
A South African High Court ruled last month that the decision by Mr. Zuma’s cabinet to withdraw from the international court was premature and procedurally irrational. The High Court added that the government could not make the decision without the approval of Parliament.
South Africa acknowledged that point in its letter to the United Nations.
It is possible that South Africa will now seek approval from lawmakers, some experts said, given that the government would probably lose an appeal of the High Court decision.
“It’s possible that they withdrew this so they can now follow the correct procedure,” said Pierre de Vos, a constitutional law professor at the University of Cape Town. “Obviously, the process has been tainted, and it’s not going to help them by appealing the judgment of the High Court. So the easier way is to just nullify the whole process and follow the correct process as the High Court indicated.”
Mr. Zuma’s party, the African National Congress, has an overwhelming majority in Parliament, and any legislative effort to withdraw from the international court would most likely succeed.
As of Wednesday morning, the South African government had made no comment on the decision, which came after Gambia’s new president, Adama Barrow, overturned his predecessor’s move and said that his country would remain in the international court.
South Africa and other critics of the international tribunal, which was created to prosecute war crimes and crimes against humanity, say that the body has mostly pursued Africans while turning a blind eye to more politically powerful leaders elsewhere.
Critics also point out that the United States, which opposed the creation of the court because it feared its officials would be subject to unfair treatment, has not joined it.
Mr. Zuma’s government announced in October that South Africa would leave the court, a year after an episode involving President Omar Hassan al-Bashir of Sudan.
Mr. Bashir, who is wanted by the international court on genocide charges, traveled to South Africa in 2015 to attend a meeting of the African Union, and South Africa, as a member of the court, was legally required to arrest him.
But Mr. Zuma’s government allowed Mr. Bashir to leave the country, arguing that heads of state had immunity during the African Union summit meeting.