A locust infestation sweeping the Horn of Africa reached Uganda on Sunday, a government minister said as the prime minister convened an emergency meeting to address the pest invasion.

"The locusts entered Uganda today" from Kenya, said Moses Kizige, the minister in charge of the northeastern Karamoja border region where the insects were spotted. The locusts have devastated food supplies in Kenya, Ethiopia and Somalia, with the Food and Agriculture Organization (FAO) describing the situation as the worst in 25 years.

Somalia declared a state of emergency this month as unusually large swarms of the hungry insects gorged on crops.

Desert locusts - whose destructive infestations cause major crop damage and hunger - are a species of grasshopper that live largely solitary lives until a combination of conditions promote breeding and lead them to form massive swarms. Swarms formed in eastern Ethiopia and northern Somalia have moved through the region.