RIO DE JANEIRO - Negotiators Tuesday reached agreement on a draft statement to be submitted for approval to world leaders meeting for the Rio+20 summit on sustainable development later this week, delegates said.

"It was adopted and it will be endorsed by the heads of state and government," a diplomat told AFP.

The agreement emerged after host country Brazil shepherded overnight negotiations that stumbled over objections from Europe.

Dubbed "Rio+20," the talks come 20 years after the Earth Summit that pledged to roll back climate change, desertification and species loss.

More than 100 world leaders, including French President Francois Hollande, South African President Jacob Zuma, Prime Ministers Manmohan Singh of India and Wen Jiabao of China, are expected to attend the summit, which runs from Wednesday to Friday.

Among the absentees are US President Barack Obama, who will be represented by Secretary of State Hillary Clinton, while environment ministers will stand in for British Prime Minister David Cameron and German Chancellor Angela Merkel.

The lengthy draft outlines steps to tackle Earth's worsening environment problems and ease poverty by spurring greener growth.

The European Union had pressed for stronger commitments, notably on changes to the world's governance of the environment and on a "Sustainable Development Goals" plan that will succeed the UN Millennium Development Goals after they expire in 2015.

The statement is now expected to be endorsed by world leaders on Friday, setting down guidelines for sustainable development for the coming decade and beyond.

Claudia Salerno, head of the Venezuelan delegation, said UN member states were keen to avoid a repeat of the 2009 Copenhagen climate summit when the negotiations were turned over to world leaders and ended in a near-chaos.

Disagreements had focused on how to move forward toward a proposed "green economy", finance for sustainable development in the poorest countries and how to define the "Sustainable Development Goals" that are meant to replace the UN's Millennium Development Goals when they expire in 2015.

On the sidelines, 50,000 activists, business executives and policy-makers are attending the 10-day conference.

On Tuesday, 45 chief executives vowed to make water security a strategic priority and called for decisive action by governments. Several companies also pledged sustainable policies.

In a message to the conference, 40 figures, including former heads of state and Nobel laureates, said the scientific evidence of dangerous environmental overreach is "unequivocal."

"We are on the threshold of a future with unprecedented environmental risks," they said.

"The combined effects of climate change, resource scarcity, loss of biodiversity and ecosystem resilience at a time of increased demand poses a real threat to humanity's welfare.

Signatories included Nobel chemistry laureate Yuan-Tseh Lee, Brazilian Environment Minister Izabella Monica Vieira Teixeira and Gro Harlem Brundtland, the former Norwegian prime minister who in the 1980s issued a landmark report on sustainable development.