International human rights groups say gunmen in the Democratic Republic of Congo have killed a prominent rights activist in the east of the country.

In a joint statement Monday, Amnesty International, Human Rights Watch, and Front Line called on Congo's government to investigate the slaying of Pascal Kabungulu Kibembi. He was executive director of the human rights group Heirs of Justice, based in Congo's South Kivu region.

The organizations say that on Sunday, three armed men in uniform broke into Mr. Kabungulu's home in Bukavu, and shot him in front of his family.

The groups are urging the Congolese government to find and prosecute those responsible and to develop an effective plan to protect human rights workers.

They say some rights activists have fled the country because of increased threats.