Facing a new U.N. call for an international investigation into alleged Syrian attacks on protesters, Luis Moreno-Ocampo, the chief prosecutor for the International Criminal Court, issued a statement Friday reminding the world that he currently has no legal authority to open such a probe.

Only the U.N. Security Council, which is divided over how to respond to the Syrian crackdown by President Bashar al-Assad, can grant the prosecutor the authority to do so.

“The Office of the Prosecutor of the International Criminal Court (ICC) has received communication from various parties alleging that crimes against humanity, including arbitrary detentions, killings of peaceful demonstrators and torture are being committed in Syria,” according to Florence Olara, a spokeswoman for the prosecutor. “The Office of the Prosecutor at this stage has no jurisdiction to investigate these allegations because Syria is not a State Party to the Rome Statute which governs the ICC.”

Navi Pillay, the U.N. High Commissioner for Human Rights, asked the U.N. Security Council Thursday to authorize an ICC investigation into alleged Syrian crimes, citing mounting evidence that the government has committed crimes against humanity during its five-month long military operation against mostly peaceful anti-government protesters.

Her office released a report Thursday that documented “widespread and systematic” abuses by Syrian security forces. It claims to have identified the names of 1900 civilians who have been killed since the upheaval began in mid-March. Her office has compiled a confidential list of 50 Syrian officials suspected of committing such crimes.

The United States, Britain, France, Germany and Portugal, have begun negotiating a resolution that would sanction Syria for its conduct. Philip Parham, the deputy ambassador for Britain, which is leading the drafting process, said it was not clear whether the draft would call for an ICC prosecution in Syria. But he said: “I don’t want to pre-empt discussion in the Council, but I would say that several members of the Council in the discussion we just had made the point very clearly that those responsible for the violence need to be held accountable.”

The U.N. Human Rights Council, meanwhile, will convene a special session on Monday to consider Syria’s human rights record in recent months. It remains unclear whether the rights council will recommend a role for the ICC, but a senior council diplomat, who spoke on condition of anonymity, said it was likely the council would make some statement calling for perpetrators of serious crimes to be held accountable.

The International Criminal Court was established in 2002 to prosecute the most serious crimes, including crimes against humanity and war crimes. It has jurisdiction only over countries that have signed and ratified the treaty, known as the Rome Statute, establishing the tribunal. The sole exception is when the U.N. Security Council decides to launch an investigation into abuses in countries that have not ratified the treaty, as it has done in Sudan and Libya.

The ICC is currently carrying out investigations into atrocities in the Democratic Republic of Congo, Northern Uganda, the Darfur region of Sudan, the Central African Republic, Kenya and Libya.