Phocas Bakaza An official from Burundi’s ruling party was killed late on Wednesday, a local administrator said on Thursday.

Bakaza, a member of the CNDD-FDD party in Mutimbuza area near the capital Bujumbura, was shot dead late on Wednesday. Two people have been arrested in connection with the attack, district administrator Damien Barindambi said.

This incident is the latest in a wave of tit-for-tat killings that U.N. officials fear is pulling the nation back into conflict.

According to U.N officials and rights groups, more than 400 people have been killed in politically motivated violence since President Pierre Nkurunziza’s announced his bid for a third term in April 2015.

Opponents said his move violated the constitution and a peace deal that brought the country’s 1993-2005 civil war to an end. However, the government referred to a subsequent court ruling that said he could run again, and he went on to win a disputed vote in July.

The crisis puts forth the risk of driving Burundi back to the kind of ethnically charged conflict that characterized the war, in which 300,000 people lost their lives, U.N. officials said.

The eruption of violence led to some 250,000 people fleeing the country, most to border camps in neighboring Tanzania.

Officials said armed men from among those refugees may have been responsible for a separate attack on Monday near the border in Burundi’s Ruyigi district, in which five people died and seven were wounded.

“Based on what the population is saying, one can conclude that the attackers are Burundian refugees from Tanzania,” another regional administrator, Gisuru Aloys Ngenzirabona, told Reuters.

Tanzanian officials could not be reached for comment.

A Burundi soldier was also killed on Thursday when an armed group attacked a military camp northwest of Bujumbura, an army officer reported to media. There was no immediate official comment.

Three groups, including one led by officers behind a failed May coup, have staged armed rebellions against the government, officials say. None have claimed responsibility for the latest attacks.

Such incidents are likely to feed into concerns that the violence could extend to the volatile Great Lakes region, which is still haunted by Rwanda’s 1994 genocide. Rwanda and Burundi have the same ethnic mix, with a Hutu majority and Tutsi minority.