COPENHAGEN -- Connie Hedegaard's surprise resignation as president of the U.N. climate talks highlighted the mayhem inside and outside the conference site today as senior-level negotiations among the 193 nations gathered here formally began.

At the beginning of today's plenary session, Hedegaard formally stepped down and said Danish Prime Minister Lars Lokke Rasmussen -- her replacement -- is more appropriate to lead the formal talks now that they have ascended to the senior level and many heads of state have begun arriving. But privately, officials here said that she was forced to step down because of questions over the strength of her leadership and close ties to the U.S. and other developed nations.

Her resignation comes after poor nations -- led by those in Africa -- on Monday protested her decision to mix together two separate negotiations aimed at extending the 1997 Kyoto Protocol and coming up with a new separate treaty. Major developing nations like China, India, South Africa and Brazil also today protested an expected Danish text coming out that they said would favor the U.S. and other developed nations and trump their concerns over financing, emission reductions and other key issues.

U.N. climate chief Yvo de Boer will continue to lead the informal discussions.

Protesters also tried to block the negotiations from continuing, with reports of more than 200 arrested. Danish police fired tear gas and beat protesters with batons outside the Bella Center, and no one at all was permitted to enter the conference site in the early afternoon when the protests were continuing. Inside the Bella Center, Friends of the Earth organized a large sit-down, and activists for indigenous groups marched and chanted through the halls.