The environmental group Greenpeace urged Prime Minister Yukio Hatoyama on Thursday to attend a key U.N. conference Dec. 7 to 18 in Copenhagen to exert his political leadership in crafting a new framework on climate change.

Before presenting 651 messages collected by the group asking Hatoyama to go to Copenhagen, a Greenpeace activist wearing a mask of the prime minister carried a large airline ticket for the Danish capital in a demonstration near the Diet.

Thomas Henningsen, a Greenpeace official in Germany, said he expects Hatoyama to follow up on Japan's target of cutting heat-trapping gas emissions 25 percent by 2020 from 1990 levels and prod other nations, like the U.S., to be equally ambitious.

"The most important thing is that (Hatoyama) goes personally to Copenhagen," Henningsen said. "Only if heads of states are going will we have a chance to cut a real deal."

Henningsen said Greenpeace is trying to motivate Hatoyama "to do what he's elected for, not only to work for the Japanese government but to work as a global leader for the survival of the planet."