GLENEAGLES, Scotland -- In a display of resolve following subway bombings in London, leaders of the major industrial nations pledged Friday to boost aid to Africa, help finance the Palestinian Authority, and bring China and India into what they called a "new dialogue" on global warming.

Meeting at a secluded Scottish golf resort, leaders from the Group of 8 wrapped up their closely watched summit slightly ahead of schedule so British Prime Minister Tony Blair could return to London to oversee his government's response to Thursday's attacks.

"We speak today in the shadow of terrorism," Blair said before leaving. "But it will not obscure what we came here to achieve. ... We offer today this contrast to the politics of terror."

As their nations' flags fluttered at half-staff outside, the G-8 leaders issued a series of communiques presenting what they described as a collective determination to tackle some of the world's most vexing challenges.

Yet on the two signature issues Blair had placed at the top of the summit agenda, Africa aid and climate change, the leaders avoided being tied down to the specific country-by-country targets sought by environmental and relief groups.

"It isn't all that everyone wanted," Blair acknowledged. "But it is progress; real, achievable progress."

President Bush left Gleneagles resort about an hour earlier than planned, without commenting publicly on the summit agreements, which some observers said had been watered down in response to U.S. pressure.

"There's been no movement from the Bush administration," said Jennifer Morgan, climate change director for the World Wildlife Fund. "Even the very noble efforts of Prime Minister Blair to get President Bush to change his position have failed."

For months, the summit had been a focal point for critics of globalization, advocates of Third World development and debt relief, and supporters of new efforts to address the environmental risks posed by global warming.

Millions of people tuned into worldwide broadcasts of last weekend's "Live 8" concerts organized by rock musicians Bob Geldof and Bono. Tens of thousands gathered in the Scottish capital, Edinburgh, to focus attention to the gathering at the Gleneagles resort 40 miles to the northwest. A few clashed with police, smashed car windows and disrupted traffic closer to the summit site.

But the sense of urgency escalated after the bombings, which some authorities believed were timed to coincide with the summit. The explosions forced G-8 leaders to revise their agenda so Blair could tend to the crisis.

The G-8 members represent the United States, Britain, France, Germany, Italy, Canada, Japan and Russia. Also attending the summit were the leaders of China, India, Mexico, Brazil and seven African nations, as well as U.N. Secretary-General Kofi Annan and the heads of the International Monetary Fund and World Bank.

Most of the declarations endorsed by all G-8 members had been anticipated, and the final negotiations generally involved the nuances of multinational policy and the niceties of diplomatic language. Although the organization has no formal authority to legislate or enforce its decrees, its members generally feel bound by the commitments they make during summits.

Among the significant new initiatives announced was a pledge to provide $9 billion in aid over three years to the Palestinian Authority to help it establish a democratic government, provide security and rein in militants as part of an ongoing peace process with Israel.

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Blair said the G-8 members agreed to provide the assistance Thursday evening, after the London attacks underscored the dangers posed by extremists. But U.S. officials said the initiative was added to the agenda last week in response to a proposal by former World Bank President James Wolfensohn.

U.S. Deputy national security adviser Faryar Shirzad, the only U.S. official to participate with Bush in all of the G-8 deliberations, said the funds would help the Palestinian Authority "spur the kind of economic development and governance necessary for them to develop a capability to govern."

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The Africa aid pledge came after members met Friday morning with the leaders of seven African nations. The agreement calls on G-8 nations to double by 2010 their development assistance to the continent, which current stands at $25 billion a year. That increase was part of a broader commitment to boost development aid around the world by $50 billion a year.

The G-8 members also ratified an agreement by their finance ministers to write off about $40 billion in debt owed to multinational organizations by 18 poor countries, 14 of which are in sub-Saharan Africa. The deal will reduce annual debt service obligations by about $1 billion.

But Blair had to abandon his efforts to persuade the G-8 members to increase their overall development aid budgets to 0.7 percent of their nations' gross domestic product.

While Bush had promised to double U.S. aid to Africa to about $8 billion a year by 2010, it would require a far bigger increase to reach the 0.7 percent target. The total American aid budget amounts to less than 0.2 percent of gross domestic product, placing the United States 21st on a list of 22 industrial economies.

Blair's biggest disappointment might have been his inability to get Bush to consider entering into any kind of pact requiring specific reductions in emissions of carbon dioxide and other gases that contribute to global warming. The United States is the only G-8 nation that has refused to sign the 1997 Kyoto Protocol mandating such cuts.

Instead, Blair got an agreement acknowledging that human activity is a probable cause of global warming, and a commitment to launch multinational talks on climate change this year.

The so-called "action plan" was endorsed by the leaders of China, India, Mexico, Brazil and South Africa, fast-growing economic powers who are becoming big consumers of oil and other pollution-producing fuels.