Gunmen have shot dead an opposition official in Burundi, witnesses said on Tuesday, the latest in a spate of killings after the disputed re-election of President Pierre Nkurunziza.

Witnesses heard gunshots in the capital Bujumbura’s Gasenyi district on Monday evening and later found Patrice Gahungu, a spokesman for the opposition UPD Zigamibanga party, dead in his car. A police officer said he was shot near his home.

"It is a political assassination because he had no problem with any one,” Clemence Nsabiyimbona, his wife, told Reuters. "In this country when you openly oppose the ruling party and the government, you are automatically an enemy worth being killed.”

Burundi was plunged into a political crisis in late April when Nkurunziza announced he would seek a third term, which opponents and Western powers said violated a peace deal that ended an ethnically charged civil war in 2005.

Protests in April and June left dozens dead and prompted tens of thousands others to flee.

In August, unidentified gunmen killed General Adolphe Nshimirimana, who was in charge of the president’s personal security before a former army chief, Colonel (rtd) Jean Bikomago, was shot dead. A local leader of the ruling party was also killed, while a prominent rights activist was shot and wounded.

Nkurunziza was sworn in on August 20 for another five-year term. New ministers were sworn in last month and some of them had been part of the opposition, drawing criticism from other opponents who said the cabinet was not legitimate.