The ongoing UN climate change conference has created two new groups of 50 nations on the forum's two key topics in a bid to speed up negotiating towards a binding deal, Mexico's Chief Negotiator Luis Alfonso de Alba told a press conference Wednesday.

"The grouping is not fixed and the positions may vary," de Alba, Mexico's ambassador to the United Nations, told journalists. "There may or may not be agreement, but it is not a closed-door session. No state was barred access."

Bolivia's negotiators reportedly disagreed with the exercise and quit the talks, but they were invited to join or risk being left on the margins.

Bolivia can come back any time, and "its seat is still there," he said.

The new groups, led by ministers or delegates, will tackle topics that have caused problems over the last 10 days. These include mitigation, or the reduction of emissions; adaptation, namely the changes to be made due to climate change. Among other topics were financing, the Kyoto Protocol and the Bali Roadmap.

The discussions began in the afternoon and may well run until midnight. The important thing is that agreements emerge from that can be sent back to the working groups, de Alba said, warning that such revisions would not be definitive.

He said that Mexican President Felipe Calderon and Foreign Minister Patricia Espinosa are making this additional effort and it is not true that the situation is repeating the pattern of last year' s Copenhagen conference.

"The goal is to make work easier, building bridges, and detailing positions where there are points of convergence," he said.

The UN climate change conference, running from Nov. 29 to Dec. 10 in the Mexican resort of Cancun, aims at finding solutions to global climate change. Participants include some 25,000 government officials, businessmen as well as members of nongovernmental organizations and research institutions from more than 190 countries.