"The situation in the Central African Republic is deteriorating daily and the number of civilian victims affected by serious crimes continues to rise," International Criminal Court Chief Prosecutor Fatou Bensouda said in a statement.
The United Nations said fighting last week in CAR left at least 20 people dead. Seleka rebels ousted President Francois Bozize and appointed their own leaders in Bangui. Bozize said rebels had help from Chadian forces.
U.N. Secretary-General Ban Ki-moon said there were reports of rape, use of child soldiers and other grave violations of international laws in CAR. Bensouda said the International Criminal Court holds jurisdiction over such crimes committed in the country.
"The people of the Central African Republic have already suffered too much," she said. "I will not hesitate to prosecute those responsible for their suffering."
U.N. Undersecretary-General Jeffrey Feltman met in Cameroon with CAR Prime Minister Nicolas Tiangaye to express commitment to agreements between the Seleka coalition and the CAR government.
That deal, dubbed the Libreville Accords, calls for elections within three years and the continued tenure for Tiangaye.