The International Criminal Court’s (ICC) chief prosecutor has appealed to witnesses to send evidence to aid an urgent investigation opened by his office into allegations of war crimes and crimes against humanity in Sudan’s Darfur region.

Sudan has been mired in war since April last year when a rivalry between the leaders of the Sudanese Armed Forces (SAF) and the paramilitary Rapid Support Forces (RSF) exploded into violence.

Four weeks of fighting in and around el-Fasher, the capital of North Darfur, has killed more than 190 people and wounded 1,200, according to medical charity Doctors Without Borders, known by its French initials MSF.

“I am extremely concerned about allegations of widespread international crimes being committed in el-Fasher and its surrounding areas,” ICC prosecutor Karim Khan said in a video statement on Tuesday, adding that the investigation “seems to disclose an organised, systematic and a profound attack on human dignity”.

His investigators had seen credible allegations of what looked like ethnically motivated attacks against the civilian population, widespread use of rape and attacks against hospitals, Khan said, calling for anyone with possible evidence, video or audio material to submit it to his office.

Khan’s statement came days after an RSF attack forced the closure of a main hospital in el-Fasher on Sunday. The group fired shots and looted the hospital, MSF reported.

Home to more than 1.8 million residents and displaced people, el-Fasher is the only state capital in the vast Darfur region not under RSF control and a key humanitarian hub for a region on the brink of famine.

The ICC has long been investigating atrocities in Sudan, dating back to a previous devastating conflict in Darfur.

The Hague-based court can prosecute war crimes, crimes against humanity, genocide and in some cases, the crime of aggression if committed on the territory of one of the court’s 124 member states or by nationals of ICC members. It can also have jurisdiction through a referral by the United Nations Security Council, as happened with Darfur in 2005.