At least six Americans have been exposed to the Ebola virus during a deadly outbreak in the Democratic Republic of Congo, sources have told CBS News, the BBC's US partner.

The World Health Organization (WHO) has declared the outbreak in DR Congo as an international emergency, with 336 suspected cases and 88 deaths reported.

One American is believed to be experiencing symptoms, while three others are said to have faced a high-risk contact or exposure. It is unclear whether any of them have been infected.

The US Centers for Disease Control and Prevention (CDC) said it was supporting the "safe withdrawal of a small number of Americans who are directly affected", but did not confirm how many.

The current strain of Ebola is caused by the Bundibugyo virus, for which there are no approved drugs or vaccines.

There are also two confirmed cases and one death in Uganda, according to the CDC.

The US government is reportedly looking to arrange transport for the small group of Americans in DR Congo to a safe quarantine location, a source told health news site STAT.

Quoting a source, the site adds that the group could be taken to a US military base in Germany, though this has not been confirmed.