"Our people are dying," Sierra Leone's leader Ernest Bai Koroma said, adding that the world was not responding fast enough as children were being orphaned.
Fears have heightened that the deadly virus could be spreading further afield
On Thursday, a Liberian doctor died of the disease at a treatment centre in Monrovia, health officials said.
Ugandan-born John Taban Dada had been working at the country's largest hospital, the John F Kennedy Memorial Center, his former colleagues said.
His death brings to four the number of doctors who have died in Liberia since the outbreak.
Liberia has been one of the worst affected countries
Meanwhile, Ms Romero is now being helped with her breathing in hospital in Spain, according to her brother. Two doctors who treated her have also been admitted for observation.