Mr Bush made the announcement at a joint press conference with British Prime Minister Tony Blair who is in Washington promoting his plan to eradicate African debt ahead of next months’ Group of Eight summit.
President Bush said he was working with Britain on a plan for rich countries to eliminate the debt of developing countries.
“Our countries are developing a proposal for the G-8 that will eliminate
100 percent of that debt,” President Bush said.
But Mr Bush signalled only countries “on a path to reform” should qualify for debt relief.
“Nobody wants to give money to a country that’s corrupt, where leaders take money and put it in their pocket,” he said.
Britain, which is hosting the meeting in Scotland, wants G8 countries to give more to Africa to raise an additional US$25b in aid.
Mr Blair is confident that goal would be reached before the leaders meet.
“My aim before the Gleneagles summit is that we end up with the increase in aid that the Commission for Africa report indicated, which is an extra 25 billion,” he said.
President Bush’s $674m pledge is on top of the $1.4b Washington has promised for the UN Africa fund.
“We urge the international community to join us in committing greater resources to the humanitarian needs in Africa,” Mr Bush said.
But Mr Bush would not commit to Mr Blair’s plan to raise extra aid money through international money markets.
He was also forced to defend the US stance on global warming that is at odds with many of America’s allies.
While Mr Blair called for “clear and immediate action” on climate change, Mr Bush said more research was needed into its possible causes.
“We lead the world when it comes to dollars spent, millions spent on research about climate change,” Mr Bush said.
“We want to know more about it. It’s easier to solve a problem when you know a lot about it.”
Mr Bush acknowledged that climate change is a “serious long term” problem and said the US would have to change its energy consuming habits, such as encouraging motorists to drive cars powered by hydrogen.
“Our country is going to have to diversify away from the type of automobiles we drive. It’s beginning to happen here. We’ll have more fuel cells, cars driven by fuel cells on the road next year than the past year, and more after that. We’re beginning to change,” he said.
The US has been criticised was its rejection of the Kyoto Protocol on climate change which sets targets for reducing greenhouse gas emissions.