A Red Cross official says hundreds of refugees have crossed into Uganda from Congo in the aftermath of that country's presidential election, heightening concerns about the possible cross-border spread of Ebola.

Irene Nakasiita, a spokeswoman for the Red Cross in Uganda, said Wednesday that the influx started the day after Sunday's vote and since then dozens have been arriving at a time.

She said some Congolese trying to cross the border were forced back after resisting the efforts of Ugandan health officials screening people for Ebola.

Congo's government cited Ebola in the country's northeast for a contentious decision to bar an estimated 1 million voters from the Dec. 30 election.

Nearly 600 Ebola cases have been reported, with more than 350 confirmed deaths since August.