JUBA, South Sudan (AP) — The worst locust outbreak that parts of East Africa have seen in 70 years has reached South Sudan, a country where roughly half the population already faces hunger after years of civil war, officials announced Tuesday.

Around 2,000 locusts were spotted inside the country, Agriculture Minister Onyoti Adigo told reporters. The country will try to control the outbreak, he added.

The locusts have been seen in Eastern Equatoria state near the borders with Ethiopia, Kenya and Uganda. All have been affected by the outbreak that has been influenced by the changing climate in the region.

The soil in Eastern Equatoria has a sandy nature that allows the locusts to lay eggs easily, said Meshack Malo, country representative with the U.N. Food and Agriculture Organization.

At this stage “if we are not able to deal with them … it will be a problem,” he said.

The locusts have traveled in swarms the size of major cities. Experts say their only effective control is aerial spraying with pesticides, but U.N. and local authorities have said more aircraft and pesticides are required. The U.N. has said $76 million is needed immediately.

U.S. Secretary of State Mike Pompeo on Tuesday during a visit to Ethiopia said the U.S. would donate another $8 million to the effort. That follows an earlier $800,000.

The number of locusts could grow up to 500 times by June, when drier weather begins, experts have said. Until then, the fear is that more rains in the coming weeks will bring fresh vegetation to feed a new generation of the voracious insects.

South Sudanese ministers called for a collective regional response to the outbreak that threatens to devastate crops and pasturage.