A coalition of opposition parties in Niger says it is boycotting a presidential runoff vote scheduled for March 20, claiming it will be rigged.

President Mahamadou Issoufou earned 48.4 percent of the vote in the Feb. 21 election, short of the majority he needed to avoid a second round. He was due to face the second-place finisher, Hama Amadou, on March 20.

But the opposition coalition announced Tuesday night that Amadou would not participate. A coalition statement alleged that the Constitutional Court responsible for validating election results is working with the current government to ensure Issoufou gets a second term.

Niger, one of the world's poorest countries, hosts French forces and American drones to combat the threat posed by Islamic extremists in West Africa.