Health authorities in the US have issued travel warnings for Guinea, Liberia and Sierra Leone, three African countries where Ebola outbreak has been reported.
It warned against non-essential travel to the countries where the outbreak could pose potential risk.
Director of the US Centre for Disease Control, Tom Frieden, said the centre would send 50 extra specialists to the affected areas in West Africa.
Meanwhile, Presidents Ernest Koroma of Sierra Leone and Johnson Ellen Sirelaff of Liberia, have cancelled plans to attend next U.S-Africa summit in Washington D.C
It was unclear whether the President of Guinea, Alpha Conde, would attend the summit in Washington D.C.
A top U.S official in a telephone conversation with journalists earlier on Thursday, said the issue of Ebola would be discussed in detail during side meetings at the summit.
The U.S. Assistant Secretary of State for Africa, Linda Thomas-Greenfield, said the summit would discuss the spread of the deadly Ebola disease and assistance to affected countries.
"I have spoken to all three heads of state to get from them where they see things going and what we can do to better assist them and we will be discussing that during the summit," Thomas-Greenfield said.
NAN reports that 50 African Heads of State and Government have confirmed their attendance at the summit, which has "Investing in the Next Generation" as its broad theme.
Earlier on Thursday, the World Health Organisation (WHO), said the death toll from the outbreak of Ebola in West Africa has risen to 729.