UN peacekeepers
Sudanese people walk past a member of the UN-African Union mission in Darfur (UNAMID) at the Zam Zam camp for Internally Displaced People (IDP), North Darfur, on 9 April 2015 ASHRAF SHAZLY/AFP/Getty Images

Rights group Amnesty International is calling on the Prohibition of Chemical Weapons (OPCW) to investigate on the Sudanese government's alleged use of chemical weapons against civilians in the Darfur region. Amnesty made the appeal as OPCW executive is to meet at the Hague, Netherlands, this week.

OPCW is an intergovernmental organisation that collaborate with the UN on activities to eliminate chemical weapons.

Last September, Amnesty claimed that more than 200 people, including several children, died after being exposed to chemical weapon agents, released by bombs dropped from planes and rockets.

It is believed the attacks were carried out during a large-scale military offensive launched in Jebel Marra in January 2016. The offensive has pitted Sudanese forces against the Sudan Liberation Army/Abdul Wahid (SLA/AW) rebel group, accused of carrying out attacks against the military.

Sudan, which is signatory to the Chemical Weapons Convention, has denied the allegations and called on the organisation to issue a public apology.

OPCW is the implementing body of the Convention.

Following Amnesty's latest call for an investigation, Khalid Mustafa, press attache at the Sudanese embassy in London, told IBTimes UK: " By this statement Amnesty proves that its own conclusions were declared before a proper investigation was carried out.

The envoy challenged the credibility of the report and renewed the call for a public apology.

"International humanitarian teams are active in Jebel Marra since the middle of last year, according to the UN.They would have found traces of chemical weapons because they help in health," Mustafa said.

Sudan's President Omar al-Bashir is wanted by the International Criminal Court (ICC) for alleged crimes including genocide committed during the Darfur conflict in 2003. Bashir has always rejected the charges and refuses to stand trial as his country does not recognise the ICC's jurisdiction.