BANGUI (Reuters) - An armed militia killed 34 civilians in an attack on Tuesday in Central African Republic, a government spokesman said, issuing a deadline for the group’s leader to give up the perpetrators to the authorities.

The attack was the most deadly since 14 armed groups agreed a peace deal in February that was meant to bring stability to a country rocked by violence since 2013, when mainly Muslim Selaka rebels ousted the then president, prompting reprisals from mostly Christian militia.

The group ‘Return, Reclamation, Rehabilitation,’ or 3R, attacked a number of villages in the northwest region Pahoua, seeking revenge for the killing of an ethnic Peul, government spokesman Ange Kazagui said at a joint briefing on Wednesday with the United Nation’s MINUSCA peacekeeping mission.

The government calls on 3R leader Sidiki Abass to “arrest and hand over those responsible for this massacre to the authorities in the next 72 hours or risk being held personally responsible”, Kazagui said.

The bloodshed will further test the peace agreement, which has already come under strain due to disagreements over representation in the cabinet.

“MINUSCA asks 3R in particular and all the armed groups in general to show strict respect for international human rights and the reconciliation and peace agreement,” MINUSCA spokeswoman Uwolowulakana Ikavi-Gbetanou said at the briefing.

The government and rebels expressed optimism when the accord was signed on Feb. 5. But lasting peace is not guaranteed: similar agreements in 2014, 2015 and 2017 all broke down.

The 3R group emerged in late 2015 to protect the minority Peul population, who are mostly Muslim cattle herders, from attacks by Christian anti-balaka militias.

Thousands of people have died because of the unrest in the diamond and gold-producing country, and a fifth of the 4.5 million population have fled their homes.