President Bush told African leaders yesterday he would "work harder and faster" to accelerate aid to the region.
Mr Bush has advocated the Millennium Challenge Account, a heavily promoted but little-used scheme, to provide badly needed assistance to nations that undertake political and economic reforms.
In his original proposal in March 2002, he proposed $5 billion for the programme by 2006. Yet three years later, the scheme has only committed $110 million to Madagascar and $215 million to Honduras.
On Monday, the programme's board approved $175 million for Nicaragua and $110 million for Cape Verde. But of that money, only $117,500 has actually been paid out.
"I assured the leaders we will work harder and faster to certify countries from MCA (Millennium Challenge Account), so that MCA countries and the people in the MCA countries can see the benefit of this really important piece of legislation and funding," Mr Bush said.
His comments came after he met privately with five democratically elected African leaders, President Festus Mogae of Botswana, President John Kufuor of Ghana, President Armando Guebuza of Mozambique, President Hifikepunye Pohamba of Namibia and President Tandja Mamadou of Niger.
They also discussed progress in the fight against HIV/Aids, which many consider their biggest development challenge. Sub-Saharan Africa is the worst-it region by the disease, which in countries such as Botswana affects one in three of the adult population.