THE HAGUE (Reuters) - Prosecutors at the International Criminal Court urged judges on Friday to report South Africa for defying an arrest warrant for Sudan’s president, saying failure to do so could render the court unable to perform its most basic duties.

Sudan's President Omar Hassan al-Bashir speaks during a press conference after the oath of the prime minister and first vice president Bakri Hassan Saleh at the palace in Khartoum, Sudan March 2, 2017. REUTERS/Mohamed Nureldin Abdallah

South Africa told the International Criminal Court it believed it was under no obligation to arrest Omar Hassan al-Bashir during a visit to South Africa two years ago even though he was wanted by the permanent war crimes court.

The ICC’s warrant did not outweigh a South African law that grants sitting heads of state immunity from prosecution, South African legal representative Dire Tladi told judges at a hearing to discuss Pretoria’s failure to arrest al-Bashir in 2015.

“There is no duty under international law and the Rome Statute to arrest a serving head of state of a non-state-party such as Omar al-Bashir,” Tladi argued.

Prosecutors said judges should refer South Africa to the United Nations Security Council or the court’s assembly of member states for defying its arrest warrant.

“Without cooperation from the state parties in the arrest and surrender (of suspects) the court will be unable to carry out its most basic function,” said prosecutor Julian Nicholls.

The row between South Africa and the ICC over its failure to arrest al-Bashir, who is accused of genocide and war crimes, led to Pretoria’s notifying the United Nations last year that it would withdraw from the court.

Earlier this year, a South African court blocked the move over procedural issues, but the government has said it will push ahead with the withdrawal.

Al-Bashir denies the charges against him. Though Sudan is not a member of the ICC, the court has jurisdiction by virtue of a 2005 U.N. Security Council resolution referring the conflict to the Hague-based permanent war crimes court.

Friday’s hearing was called so that the court could gather information on whether it should report South Africa either to the ICC’s governing body, the Assembly of State Parties, or to the U.N. Security Council for non-compliance with the court.