The US government on Tuesday formally pledged to reduce greenhouse gas emissions by 26-28 percent over 2005 levels within the next decade, ahead of a major climate conference later this year.

President Barack Obama made the same pledge during a meeting with Chinese President Xi Jinping in November.

But this formal submission to the United Nations commits this and future administrations to the target.

"For decades, we've known why global average temperatures are rising," said White House advisor Brian Deese, announcing the goal.

"It's past time we heed these warnings. It's past time for the world to take action."

In December, the United Nations will hold the latest round of global climate talks in Paris.

The aim is to reach a global accord that would go some of the way toward limiting the rise in global temperatures.

Countries aim to limit average global temperatures to two degrees Celsius (3.6 degrees Fahrenheit) over pre-Industrial Revolution levels.

"With today's submission of the US target, countries accounting for more than half of total carbon pollution from the energy sector have submitted or announced what they will do in the post-2020 period to combat climate change," said Deese.

Environmental groups gave the announcement a cautious welcome.

"This is a big commitment for the United States, but on its own the current offer clearly isn't enough to keep global warming below two degrees Celsius," said Jamie Henn of 350.org.

He urged the Obama administration to curb new fossil fuel development.

Oxfam said the announcement was "a critical step forward in transitioning to a clean energy economy."

French foreign minister Laurent Fabius welcomed the announcement, saying it confirmed the United States and Obama's engagement in the tackling climate change.

But the praise was not universal.

Republican Senate leader Mitch McConnell warned America's international partners that the US pledge could be reversed.

He said that even if Obama's domestic measures to implement the deal "were fully implemented, the United States could not meet the targets laid out in this proposed new plan."

"Our international partners should proceed with caution before entering into a binding, unattainable deal."