DAR ES SALAAM (Reuters) – The United States has warned its citizens to take extra care when visiting Tanzania amid concerns over Ebola, adding to calls for the East African country to share information about suspected cases of the deadly disease there.

U.S. travelers should “exercise increased caution”, the State Department said on Friday in an updated travel advisory that cited reports of “a probable Ebola-related death in Dar es Salaam”.

Tanzania denies the reports, saying no cases of Ebola have been confirmed, but with transparency key to combating the deadly and fast-spreading hemorrhagic fever, the government is under mounting pressure to provide clarification.

The foreign affairs ministry was not immediately available on Saturday for comment on the U.S. advisory.

Authorities in east and central Africa have been on high alert for possible spillovers of Ebola from the Democratic Republic of Congo, where a year-long outbreak has killed more than 2,100 people.

Tanzania and DRC share a border that is separated by a lake.

In a rare public rebuke, the World Health Organisation (WHO) last week said that, contrary to international health regulations, Tanzania was refusing to provide details of suspected cases.

Days earlier, the head of the U.S. Centers for Disease Control and Prevention traveled to Tanzania at the direction of U.S. Health Secretary Alex Azar, who had also criticized the country for not sharing information.

The WHO said that, while it was concerned by the lack of transparency, it has no evidence on the presence of Ebola in Tanzania, but ruled out punitive action and reiterated it had advised against travel or trade restrictions. 

Tanzania on Tuesday summoned the WHO’s local representative over its assertion. In mid-September, the health minister said the government had investigated two recent cases of unknown illnesses, but they tested negative for Ebola.

(Reporting by Fumbuka Ng’wanakilala; Editing by George Obulutsa and John Stonestreet)