The Swiss foreign minister, Joseph Deiss, has called on world leaders to work together to fight against global poverty.
Deiss made the call for action during a speech at the Earth summit in Johannesburg.
"The nations of the world have decided to meet here in Johannesburg because they know that global problems need global solutions," Deiss told delegates gathered for the summit's plenary session.
"But to succeed, the whole world needs to show a willingness to act together," he added.
Deiss called on those present in Johannesburg to do everything possible to reach agreement on a concrete action plan "to safeguard the future of generations still to come".
"The stakes are high: either we succeed together, or we fail together...this is a unique chance, and if we do not take it, the passage of time will not repair the mistake," Deiss said.
The foreign minister was making the speech in his capacity as head of the Swiss delegation in Johannesburg.
Around 100 heads of state attending the summit have the same opportunity to make a five-minute address over the next three days.
During his speech, Deiss also appealed to the United States - which has been widely criticised by other governments as well as environmental groups for failing to take a leading role at the summit - to take seriously the issues under discussion at the negotiating table.
"I am pleading for a global partnership," Deiss said, "and for an attitude of solidarity between industrialised nations, developing countries and those currently in a process of transition."
"I particularly invite the United States, Russia and all other countries which have been called to play a leading role not to neglect their responsibilities, notably in joining those countries which have signed the Kyoto Protocol or which are in the process of doing so."
Switzerland has not yet ratified the protocol - which seeks to cut global greenhouse gas emissions - but has submitted the text for parliamentary approval.
Describing the summit as a "political credibility test", Deiss warned conference delegates of the price of failure: "Are we ready to relegate our short-term, national interests in favour of benefiting humanity as whole? Or do we want to just sit back and watch the degradation of our planet and the depletion of the resources which will be needed by future generations?"
As Deiss and his counterparts were delivering their speeches inside the main conference hall, last-minute negotiations on the terms of a political declaration and global plan of action were entering a final, decisive phase.
Serge Chappatte, a senior Swiss negotiator at the summit, said the final round of talks between world leaders would be an opportunity for "trading off" before the announcement of an action plan to combat poverty and safeguard the earth's natural resources.
The last main stumbling block over the issue of energy finally fell into place on Tuesday morning, when countries agreed to "substantially increase" their share of renewable energy without setting any specific targets or deadlines.
Twenty-four hours earlier, agreement was also reached on one of the major issues Switzerland has been championing at the negotiating table: setting a target of 2015 for halving the number of people without access to both clean water and proper sanitation.
swissinfo, Ramsey Zarifeh, Johannesburg
The Swiss foreign minister, Joseph Deiss, has called on world leaders to work together to fight poverty and safeguard the future of the planet.
Deiss made the call in his capacity as head of the Swiss delegation at the Earth summit in Johannesburg.
A global action plan designed to fight poverty and safeguard the world's natural resources is expected to emerge on Wednesday.
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