"It is unfortunate that we failed to reach a legally binding agreement," Japanese Prime Minister Yukio Hatoyama told reporters in New Delhi when asked about the Copenhagen talks.

Hatoyama said he discussed the Copenhagen initiative and climate change issues in a bilateral meeting he had with Prime Minister Manmohan Singh.

"With the cooperation of countries, we need to make that (Copenhagen Accord) into a legally binding agreement," he said after the meeting with Singh.

A joint statement issued after the talks said that the two leaders welcomed the Copenhagen Accord. Singh and Hatoyama reaffirmed their determination to work together closely in the negotiations under the UN Framework Convention on Climate Change and agreed outcome to be adopted at the 16th Conference of Parties next year.

Singh welcomed the announcement of the 'Hatoyama Initiative' under which Japan has pledged to reduce its own emissions by 25 per cent in the next decade and to work closely with developing countries on their mitigation programs.

The Copenhagen Accord, agreed to by 119 heads of state/government, is not a legally binding document and does not mention any quantitative emission targets for any country.