The International Criminal Court's prosecutor says she is opening a new investigation into atrocities including murder, rape and persecution during ruthless sectarian fighting since 2012 in the Central African Republic.

Months of fighting between the mostly Muslim Seleka rebel coalition and the Christian anti Balaka militia have left at least 5,000 people dead in one of Africa's least developed countries.

Prosecutor Fatou Bensouda said Wednesday "the list of atrocities is endless. I cannot ignore these alleged crimes."

It is the court's second investigation in the Central African Republic. In the first, a former Congo vice president, Jean-Pierre Bemba, is on trial on charges of commanding rebels who committed murder, rape and pillaging in the country. Bemba is awaiting verdicts in the trial that began in 2010.