"I trust that we will fight to the last minute," Steinmeier said on Monday. "We need binding benchmarks and targets and we have to see whether we can make more headway."
With a week to go before the June 6-8 summit in the Baltic Sea resort of Heiligendamm, the United States and its partners in the Group of Eight leading industrial nations appear to be heading for a major clash on climate change.
According to leaked documents, Washington has rejected parts of a draft declaration on curbing global warming which Germany, as current G8 president, wants leaders to adopt at the meeting.
The US administration rejects the idea of setting mandatory targets on greenhouse gas emissions, as well as language calling for G8 nations to raise overall energy efficiencies by 20 percent by 2020.
German Chancellor Angela Merkel's proposed text on the environment calls for limiting the worldwide temperature rise this century to two degrees Celsius (3.6 degrees Fahrenheit).
It also stresses the need to cut global greenhouse gas emissions to 50 percent below 1990 levels by 2050.
Hinting at a row with Washington, Merkel said last week she was pessimistic that the G8 summit would result in a commitment to cut greenhouse emissions.
Steinmeier said some progress has been made in forging an understanding between Europe and the United States but urged Washington to come on board on energy efficiency targets before the G8 gathering.
"We trust that the US will be prepared to work together with us in the field of energy technology," he said. "We need to do this."
He was speaking after a meeting between the so-called EU troika -- grouping the German and Portuguese foreign ministers and EU foreign policy chief Javier Solana -- and Chinese Foreign Minister Yang Jiechi.
Germany is seeking to tie both China and India into a new pact on fighting carbon emissions after 2012 when the Kyoto Protocol runs out.
Together, the two vast developing nations are set to surpass the United States' output of greenhouse gases in 2015. The German chancellor has warned that efforts to fight global warming were doomed without them.
Unlike the United States, China signed up to Kyoto but its status as a developing nation exempts it from binding emissions targets.
Yang refused to be drawn on whether Beijing would agree to be tied to emission limits in the post-Kyoto era, saying China needs to strike a balance between fighting pollution and fighting poverty.
"Our position is that we are a developing nation and climate change is not the doing of developing countries, though every country has to do what it can to help the environment," he said.
"China's greenhouse emission per capita is lower than in the developed world and we still have a substantial number of people living below the poverty line, so we have to strike a balance between development and protecting the environment."
A serious blow
Earlier Monday, Merkel's efforts to rally the developing world on climate change received a serious blow when India, which had been invited to the Heiligendamm summit, said it would reject proposals to limit greenhouse gas emissions.
The Indian environment ministry said restrictions would slow the country's boooming economy and set back efforts to fight poverty.
The EU-China meeting took place on the sidelines on an ASEM meeting of EU and Asian nations in Hamburg which concludes on Tuesday.