COPENHAGEN - U.N. Secretary-General Ban Ki-moon and Danish hosts urged countries on Tuesday to compromise to salvage agreement on a new U.N. pact aimed at averting dangerous climate change.

Ministers were struggling to break deadlock in global climate talks in Copenhagen, three days before world leaders were due to seal an accord.

In these very hours we are balancing between success and failure, said Danish President of the two-week meeting, Connie Hedegaard, at the opening of the high-level phase of the talks.

Success is within reach. But ... I must also warn you: We can fail. Organisers of the talks said environment ministers would work deep into night on Tuesday to narrow wide differences, saying the bulk of the work must be complete before some 115 leaders formally join the meeting on Thursday.

Three years of effort have come down to three days of action, Ban said. Let us not falter in the home stretch. No one will get everything they want in this negotiation.

After a suspension of several hours the previous day, talks were stalled on Tuesday over disputes about the level of emissions cuts by rich countries and a long-term global target to curb a rise in global temperatures which could trigger rising sea levels, floods and drought.

Draft texts dated Tuesday showed that national negotiators had stripped out figures for long-term global goals and rich nation emissions cuts by 2020 from last week's U.N. texts. The numbers could be re-inserted if agreement is reached.

Major U.S. businesses including Duke Energy, Microsoft and Dow Chemical called for tough U.S. emissions cuts which would mobilise a shift to a greener economy.

There's a great deal yet to do, the parties are quite far apart on a fair number of issues, said Todd Stern, U.S. special envoy for climate change, adding he did not expect any change in U.S. targets for emission curbs during the talks.

Climate