South Africa's withdrawal from the International Criminal Court has been revoked, the United Nations secretary-general says, stalling what would have been the first-ever departure from the tribunal that pursues the world's worst atrocities.

A notice dated Tuesday on the U.N. treaty website says the move comes after a South African court ruled last month that the country's decision to withdraw without parliament's approval was unconstitutional.

South Africa shocked the international community last year when it informed the U.N. chief it would withdraw from the court that pursues cases of genocide, war crimes and crimes against humanity. Withdrawal comes a year after notification.

South Africa had been on track to be the first country to leave the tribunal, which is based in The Hague, Netherlands, and has more than 120 member states.

South Africa's main opposition party challenged the withdrawal in court, saying it was illegal because parliament was not consulted. "South Africa does not want to be lumped together with pariah states who have no respect for human rights," the Democratic Alliance said after the court decision.

It was not clear whether South Africa would challenge the court's decision or continue to pursue an ICC withdrawal with the approval of parliament, where the ruling African National Congress party has a majority and likely would support it.

Three African countries last year made moves to leave the ICC, speaking fears of an African exodus. Only Burundi remains on a path to withdrawal. Gambia under new President Adama Barrow also has revoked its withdrawal.