U.S. President Barack Obama gestures during a press conference at the G20 Summit at the ExCeL centre in London on Thursday. (Kirsty Wigglesworth/Associated Press)

Echoing comments made by other world leaders in attendance, U.S. President Barack Obama praised the communiqué agreed upon at the London G20 summit, calling it the "turning point" in efforts to revive the ailing global economy.

"We laid the groundwork for real and lasting progress on a host of issues," Obama said. "But I believe this is just the beginning."

"This document will help put an end to the bubble and bust economy that prohibits sustained growth," he said.

In addition to the more that $1 trillion US world leaders pledged to help stimulate the global economy, Obama also pledged an additional $448 million to support developing economies in Africa.

But he painted the expenditure as an investment, rather than charitable aid.

"These are all future markets for all economies," he said.

Obama called the summit a success for recognizing the global nature of the crisis.

When asked, however, he could not point to an individual summit accomplishment that would help recession-battered Americans beyond general points such as fighting protectionism and working together to keep the global economy functioning.

But, he said, the summit communiqué "affirms the need for all countries to take fiscal responses that increase demand, that encourages the openness of markets. Those are all going to be helpful in us being able to fix what ails the economy back home."

"This is not a panacea, but it is a critical step," Obama said.

Dialogue, consensus emphasized

He said he was committed to "forging a consensus instead of dictating our terms" and argued that the United States acting alone would only be "half-way effective, not even half."

He declined to specify where the White House compromised, saying the final communiqué reflected a consensus of world leaders.

In particular, he spoke out against tax havens and the "shadow banking system" that British Prime Minister Gordon Brown, in particular, has blamed for exacerbating the financial meltdown.

"We will identify jurisdictions that refuse to co-operate, including tax havens, and we will take action against them," Obama said.

Obama said he had also met with other heads of state on the sidelines of the summit, which he said was "a turning point in our pursuit of global economic recovery."

He said he had had one-on-one talks with leaders of Russia, China, Great Britain and India on topics that included ways to "reduce the nuclear threat" throughout the world. He called for a co-ordinated response to North Korea's plans to launch a multi-stage rocket in the coming days.

With files from the Associated Press