Denmark has formally invited the leaders of United Nations member countries to the U.N. conference in Copenhagen in December that will try to clinch a new global climate deal, Reuters quoted the government as saying today. "The invitations are sent by letter from Prime Minister Lars Lokke Rasmussen to the heads of state and government of the other 191 U.N. member states," a government statement said. The part of the conference for heads of state and government will be on the last two days of the conference, though a government spokesman said the leaders were welcome to come earlier if they like. The Copenhagen talks were originally meant for environment and climate ministers but the United Nations said last week that about 40 leaders have indicated plans to attend, including British Prime Minister Gordon Brown and leaders of nations in Africa, the Caribbean and Latin America. U.S. President Barack Obama has said he would go to Copenhagen if his presence could make a difference to secure a deal, and German Chancellor Angela Merkel signalled on Tuesday she would go.