Police detained at least 40 people Friday in the first street protests linked to a two-week climate conference in Copenhagen as negotiators prepared for the final stage of talks on controlling the world's greenhouse gases.

About 200 people rallied in the downtown area where corporate CEOs were meeting to discuss the role of businesses in the fight against global warming — one of many side events to the U.N. conference that started Monday.

Protesters broke into small groups, banging drums and shouting "Mind your business, this is our climate!"

Police spokesman Henrik Moeller Nielsen said the detentions were preventative to avoid disorder. There were no reports of violence.

Negotiators in Copenhagen are trying to agree on a global pact to reduce greenhouse emissions and help poor countries deal with climate change.

A difficult issue is the split between the United States and China on how national pledges to control carbon emissions can be monitored so that all countries can ensure promises are kept.

The conference also will have trouble reaching agreement on long-term financing amounting to as much as $150 billion (euro100 billion) a year to help developing countries ward off devastating effects of global warming, from rising sea levels threatening coastal cities to floods and droughts devastating agriculture.

The U.S. says it supports such funding but cannot come up with a figure for its own payout until Congress enacts a climate and energy bill next year.

In Brussels, the leaders of France and Britain said Friday that EU nations will commit more than euro2 billion ($3 billion) a year to help poorer countries combat global warming.

Britain's Gordon Brown and France's Nicolas Sarkozy said their two countries would contribute most of that sum and were trying to get smaller members of the 27-state European Union to pitch in more.

EU leaders failed Thursday to come up with a firm figure for the fund, an embarrassing setback for a bloc that was long at the forefront of the fight against global warming. Smaller eastern EU states were reluctant to donate as they struggle with government debt and rising unemployment in the wake of the financial crisis.