South African President Cyril Ramaphosa says he is determined to pursue its genocide case against Israel at the International Court of Justice and will next month file more evidence, AFP reports.

South Africa filed the case in December alleging that Israel’s Gaza offensive breached the 1948 UN Genocide Convention. Israel has strongly denied the accusation.

“We are headstrong,” Ramaphosa told journalists when asked about the case. “We are determined to go ahead with our case.”

The country is due to file facts and evidence to the UN court next month to back up its case. “Preparations are underway to present what they call the memorial, a huge tome of hundreds and hundreds of pages,” the president said.

“We continue arguing that the genocide must stop and there must be a ceasefire, and similarly, there must be a return of the hostages.”

South Africa’s case has been joined by several countries, including Colombia, Libya, Mexico, Spain and Turkey.