A Moroccan United Nations peacekeeper has been killed in a suspected attack by members of the extremist insurgent group, Lord's Resistance Army, in Central African Republic, according to a UN statement.

UN Secretary-General Ban Ki-moon condemned the killing of the peacekeeper in Mbomou prefecture's Rafai town late Monday, the statement said.

Peacekeepers were fired upon when a patrol was dispatched to Rafai in response to an attack on nearby Agoumar Village, it said, adding: "The peacekeeper was shot by unknown assailants and succumbed to his wounds later that afternoon."

Ban said "the attacks against those who are working towards peace and security in the Central African Republic are unacceptable."

According to the U.S. Department of State, "the Lord's Resistance Army (LRA) has been active since 1986, making it one of Africa's oldest, most violent, and persistent armed groups. The LRA was formed in northern Uganda to fight against the Government of Uganda, and operated there from 1986 to 2006. At the height of the conflict, nearly two million people in northern Uganda were displaced."

In 2005, the International Criminal Court issued arrest warrants for the LRA leader Joseph Kony and four other top commanders-Vincent Otti, Okot Odhiambo, Dominic Ongwen, and Raska Lukwiya-for war crimes and crimes against humanity. Otti and Lukwiya are now believed to be dead, but the others remain at large, according to information posted on the group at the State Department's official website.

Local media reports also blame the group for abducting around 20,000 children since 1980s to either enslave them or to train them as fighters.

In 2006, the group withdrew from Uganda due to increasing military pressure there and has since been operating since on the borders of Sudan and South Sudan as well as Congo and South Sudan.