Travelers to Tanzania are being urged by the US State Department to exercise increased caution due in part to a "probable" fatal case of Ebola.
The travel alert that also cited dangers of crime, terrorism and anti-gay actions was issued on Friday.
The State Department pointed to "unofficial reports regarding the unexplained death of a person" in Dar es Salaam on September 8.
"Probable Ebola" is given as the cause of that death in the new US travel advisory.
It adds that the deceased individual had reportedly travelled while ill to the cities of Songea, Njombe, and Mbeya.
The Tanzanian government has denied that Ebola is present in the country. But authorities have refused to give outside monitors access to tests performed on the dead person identified in reports as a female doctor.
In a recent press briefing, the top US health official, Alex Azar, called on the Tanzania government "to comply with obligations for full disclosure and allow for independent investigations of the circumstances of that individual's death."
The World Health Organisation has also issued an alert based on what it said is credible intelligence of one or more Ebola cases in Tanzania.
WHO further noted that the Tanzania government has not complied with several requests for details on the suspected cases.
Ebola has claimed more than 2000 lives in a still-uncontrolled outbreak in the Democratic Republic of Congo, which borders Tanzania.
In its revised travel advisory, the US warns that "members of the LGBTI community have been arrested, targeted, harassed, and/or charged with unrelated offenses."