Climate protection is a top priority for German Chancellor Angela Merkel at next week's G-8 summit.
"If the United States doesn't move, then others will also wait and see," Merkel was quoted as saying in an advance copy of a Der Spiegel magazine interview to be published Monday.
U.S. President George W. Bush last week called for 15 leading nations identified as major emitters of greenhouse gases to meet later this year. He said he wanted the group, including the U.S., China, India and major European countries, to come up with a global goal for carbon emissions but decide themselves how to reach it.
But Merkel said that the United Nations had to be involved in any binding proposition and the U.S. could not come up with a separate proposal. "It is not negotiable for me," she was quoted as saying.
Merkel added she would not engage in "foul compromises."
The German chancellor faces a tough task in trying to achieve concrete goals for emission cuts at a Group of Eight summit on June 6-8, and is expected to meet with Bush for bilateral talks Wednesday.
The meeting begins Wednesday in the coastal resort of Heiligendamm where Merkel will also lead discussions with leaders of Britain, France, Japan, Italy, Russia and Canada on aid to Africa and the world economy.
Russian officials have repeatedly declared that Israeli aviation poses a threat to the Russian military in Syria.