The United States Centers for Disease Control and Prevention (CDC) has announced a 30-day suspension of entry into the U.S. for foreign nationals who have recently been in South Sudan, the Democratic Republic of the Congo (DRC), or Uganda.

According to the CDC, the temporary measure applies to non-U.S. citizens who have been present in any of the three countries within the previous 21 days, as American health authorities respond to the ongoing Ebola outbreak in the region.

The agency said the restriction is intended to reduce the risk of Ebola transmission into the United States, although officials emphasized that the immediate threat to the American public remains low.

Ebola has an incubation period of up to 21 days, meaning infected individuals may travel before developing symptoms.

The CDC said that U.S. citizens, lawful permanent residents, certain diplomats, military personnel, and approved humanitarian workers are exempt from the restriction.

The move follows reports that an American aid worker in the DRC tested positive for Ebola and is being transferred to Germany for treatment.

U.S. authorities have also reportedly suspended routine visa services at embassies in Juba, Kinshasa, and Kampala during the period of the health measures.

Health officials in the affected countries continue to monitor and contain the outbreak, while international agencies are coordinating response efforts.

The CDC said the restrictions will remain in place for 30 days, subject to review depending on the public health situation.