President Bush and Tony Blair met at the White House Tuesday for their first get-together since Blair's government won a close re-election last month, but prior to the meeting the British prime minister already lost out on two top priorities.

Bush served notice that he can't deliver on his British counterpart's main requests — a big boost in aid for Africa and an agreement to replace the Kyoto Protocol (search), the international global-warming treaty.

Bush did, however, agree to a modest $674 million increase in African famine-relief aid. That may take some of the sting out of Bush's opposition to Blair's proposal to double current aid levels.

Besides the $674 million, the United States has earmarked $1.4 billion requested by the United Nations to address emergency needs.

The two leaders also called on other countries to increase their commitment to deal with humanitarian emergencies in Africa.

However, the other issue topping Blair's foreign policy this year — fighting global warming — may further strain his relationship with Bush.

Blair has made both issues the twin focus of Britain's year-long chairmanship of the G-8 group of wealthy nations, and has been shopping the African aid package and climate-change initiative in other world capitals in advance of the G-8 meeting next month.

Bush aides say the United States wants to ensure that Blair's hosting of this year's economic summit of the world's seven richest industrialized nations and Russia is deemed a success. But Blair has made global warming and dramatically stepped-up aid to Africa the main topics of the July gathering, and Bush opposes most of what the British leader wants to do -- or how he wants to do it.

The Tuesday talks between Bush and Blair also touched on Iraq's halting progress toward stability and efforts to turn Iran away from nuclear weapons pursuits.

Some critics say Bush owes Blair for his unconditional support of the Iraq war despite strong British public opposition, but others say that wasn't Blair's intention. The two men also differ over the Mideast peace strategy, Guantanamo Bay detentions and other issues.

"I think he supported the Bush administration in Iraq because he believed it was the right thing to do," Christopher Makins, president of The Atlantic Council, told FOX News. "He didn't do it because he was trying to earn some entitlement for the future."

Bush indicated a week ago that Blair's $50 billion Africa aid proposal was too expensive.

"We have made our position pretty clear on that, that it doesn't fit our budgetary process," Bush said. "On the other hand, I've also made it clear to the prime minister I look forward to working with Great Britain and other countries to advance the African agenda that has been on the G-8's agenda for, ever since I've been the president."

Blair also wants nations to commit new money to Africa, rather than reallocating existing funds. But even the U.S. famine relief dollars were coming out of an already approved Agriculture Department food aid account and other money recently made available by Congress.

"It is important we deal with the situation in Ethiopia and Eritrea, but obviously, there's a lot more that needs to be dealt with," Blair said.

White House spokesman Scott McClellan said the $674 million commitment should be considered separate from any G-8 action. He said the United States is still discussing debt relief for African nations with other members of the G-8, although he would not discuss what additional aid the U.S. might be willing to commit to before Bush's meeting with Blair.

Blair did say Tuesday that his plan to ease African debt was making good progress among G-8 leaders. He also said the U.S. famine relief plan would be only a small part of the effort to boost African development.

"We are a significant way toward a deal," on African debt relief ahead of the G-8 summit in Gleneagles, Scotland, next month, said Blair, briefing reporters at the British embassy. "There are still issues we need to resolve, but I am increasingly hopeful we will get a good deal on that," he said.

Blair said the $674 million White House plan for famine relief in Ethiopia (search) and Eritrea (search), formally announced later Tuesday, was only a small step toward a $25 billion increase in African aid that he hopes to secure at the summit.

"It is important we deal with the situation in Ethiopia and Eritrea, but obviously, there's a lot more that needs to be dealt with ... the [Bush] administration itself has made clear that this is not the only commitment," he said.

The money the U.S. has already committed will be drawn from funds already approved for an Agriculture Department food aid account and other funds available in a recent supplemental appropriation.

Besides focusing on the food needs of 14 million people vulnerable to famine in Ethiopia and Eritrea, the joint initiative will address humanitarian needs in Somalia and Djibouti, McClellan said.

"The two leaders will also be calling on other countries to increase their funding to meet this emergency," McClellan said. "This is something that is needed now, in the coming months."

American support is crucial to Blair, but he may face an uphill fight to win it on global warming. The president opposes the Kyoto Protocol, and his administration questions scientists' views that man-made pollutants are causing temperatures to rise.

"I think what Mr. Blair is trying to achieve is to bring the United States back into these international discussions," Makins said of Blair's desire to return Bush to Kyoto Protocol talks.

Bush has also said indicated he's happy to go along with global-warming studies, but not a commitment to reduce greenhouse gas emissions.

His aides say any pollution-reducing actions by the United States and Western Europe would likely be more than offset by increased pollution from China, India and other developing countries. The better solution, they have said, would be to provide those nations with non-polluting technologies.

Blair wants "clear and immediate action" to address rising temperatures and said global warming is one of the world's most pressing priorities.

FOX News' Wendell Goler and The Associated Press contributed to this report.