The Commonwealth represents two billion people globally

The text, released after the second day of their summit in Uganda, is designed as a strong statement ahead of next month's UN climate talks.

But the 53-member group could not reach a consensus on binding emission cuts.

Meanwhile, India's Kamalesh Sharma has been appointed secretary general. He replaces New Zealand's Don McKinnon.

Mr McKinnon is stepping down at the end of his four-year term.

On Saturday, the Commonwealth leaders are working at a retreat on Lake Victoria, away from media attention.

Officials had said the summit would try to iron out differences between member states on climate change.

Divisions

Many Commonwealth nations, led by Britain, wanted an influential statement before next month's UN talks in Bali, which will discuss a new agreement to replace the Kyoto protocol, which expires in 2012.

But Canada had insisted that any statement should refer to the need for contributions from the world's major polluters, including the United States, which has so far resisted any binding targets.

Australia is also a major CO2 emitter. Like the US, its outgoing government has not ratified the Kyoto Protocol.

"There are clearly some (Commonwealth leaders) who are clearly not ready to use the term binding at this stage," Mr McKinnon said following Saturday's talks.

"The objective was to make a very strong political statement without getting caught up in too many technicalities ahead of Bali," he said, according to the AFP news agency.

A Commonwealth statement announced a shared goal "to achieve a comprehensive post-2012 global agreement that strengthens, broadens, and deepens current arrangements", AFP reported.

"This should include a long-term aspirational goal for emissions reduction to which all countries would contribute," the statement said.

The first day of the summit was marred by clashes between protesters and police in Uganda's capital, Kampala.

Protesters denounced Britain's Queen Elizabeth for meeting Ugandan President Yoweri Museveni, who they say abuses rights.

The three-day summit on Friday suspended Pakistan for civil rights violations under its emergency rule.

Brown optimism

A new global trade agreement is also on the summit's agenda.

It is one of the most divisive issues for the Commonwealth, which includes some of the world's wealthiest nations as well as some of the poorest.

UK Prime Minister Gordon Brown on Saturday expressed optimism that a new deal could be reached in the next few weeks.