The United States aims to reach a political deal on future reduction of greenhouse gas emissions at a UN climate change conference, the country's leading negotiator said on Monday.

"We see it (the conference) dealing with a political agreement that would be operational," Jonathan Pershing, US deputy special envoy for climate change, told a press conference on the sidelines of the UN-led conference on climate change, which kicked off Monday.

The conference had been expected to seek a legally binding deal on further reduction of greenhouse gas emissions after the first commitment period of the Kyoto Protocol ends in 2012.

Pershing said the political agreement would pave the way for a legally binding treaty in the end, of which Washington would be a party.

But he stressed all countries should be subject to legal obligations.

"It incorporates legal obligations for us, for other developed countries and for developing countries," he said.

The United States came under fire for its inadequate commitment of reducing greenhouse gas emissions, as the European Union (EU) renewed a call on Washington to do more.

EU environment spokesman Andreas Carlgren said that the endgame of the negotiation in Copenhagen would be on what will be delivered by the United States.

Carlgren said he would feel "astonished" if US President Barack Obama, who is scheduled to attend the conference together with over 100 other world leaders on the last day of the talks, did not put more on the table.

In the run-up to the Copenhagen summit, Washington pledged to reduce its CO2 emissions by 17 percent from 2005 levels by 2020, equivalent to a reduction of merely 4 percent if compared with 1990 levels.

The EU has committed itself to a voluntary reduction of 20 percent from the base year of 1990 and promised to raise the rate to 30 percent if others also aim high.

However, Pershing defended the US target of reducing emissions, saying it is based on sound scientific proof.

"What the US has put on the table is a trajectory that is not only consistent with but meets the criteria of a robust scientific outcome," he said.

(Xinhua News Agency December 8, 2009)