In Washington, the White House said the United States "joins the consensus" that the Bali climate change conference is a "critical first step" toward a plan to replace the Kyoto Protocol set to expire in 2012.
But in a written statement Saturday, the White House said it has "serious concerns" that no new agreement will work unless negotiations are based on each nation's unique circumstances and every nation's right to grow its economy.
The European Union said it is pleased with the Bali deal. Humberto Rosa, who led the EU delegation to Bali, called it "exactly what we wanted."
The EU and other countries bowed to U.S. pressure not to include specific targets for reducing greenhouse gases.
The intense talks were extended for an extra day and the agreement came after a personal appeal by United Nations Secretary-General Ban Ki-moon. He called the agreement "the defining challenge of our time."