JOHANNESBURG — Tanzania is entering its sixth week without an update on its coronavirus cases as African health authorities worry and the U.S. issues a new statement of concern.

The East African nation’s data has been frozen at just over 500 cases since the end of April as the government of President John Magufuli claims the virus has been defeated. The opposition, however, has alleged that Tanzania’s cases could be in the tens of thousands.

The latest U.S. Embassy alert, posted Tuesday, says “there have been instances during the COVID-19 outbreak when hospitals in Dar es Salaam reached full capacity due to the high volume of COVID-19 cases” and that “the risk of contracting COVID-19 remains high.”

The alert recommends that U.S. government personnel stay at home except for essential activities.

Tanzania, unlike many African nations, has lifted its ban on international flights. Cases across the African continent are now above 157,000.