The delicately balanced global climate talks in Cancun suffered a serious setback on Thursday when Japan categorically stated its opposition to extending the Kyoto protocol, the binding international treaty that commits most of the world's richest countries to making emission cuts.
The statement, made by Jun Arima, an official in the government's economics trade and industry department, was the strongest yet made against the protocol by one of the largest emitters of greenhouse gases.
He said: "Japan will not inscribe its target under the Kyoto protocol on any conditions or under any circumstances." If this proves to be more than a negotiating tactic, it could provoke a walk-out by some developing countries.
Japan, said it would not reject a new legally-binding overall agreement, but is concerned that it would be penalised if it signed up to cuts while other countries such as India and China were not legally bound to make similar cuts.