PARIS - French President Francois Hollande met with environmental groups Saturday, pushing for an ambitious global deal to reduce man-made emissions blamed for global warming - with emphasis on helping developing countries adapt to a changing world.

The talks in the Elysee Palace came as President Obama and the leaders of China, Russia, and scores of other countries prepare to converge on Paris to launch two weeks of high-stakes talks.

Leaders and climate negotiators from 196 countries meeting at the U.N. talks starting Monday will try to hash out the broadest, most lasting deal to date to slow global warming.

Saturday's meeting and the talks are taking place under extra-high security after Islamic extremists killed 130 people in Paris on Nov. 13.

Security was planned to be tight even before the attacks, given the throng of government leaders attending. French Interior Minister Bernard Cazeneuve said Saturday that just under 1,000 people thought to pose security risks have been banned from entering the country.

Later Saturday, French Foreign Minister Laurent Fabius symbolically handed over the "keys" to the climate conference to the U.N. climate change agency, which will oversee the two-week talks.

"The keys to the [conference] are now in the hands of the U.N., a symbolic key of hope," Fabius tweeted after handing over a giant key to Christiana Figueres, head of the U.N. Framework Convention on Climate Change. Figueres, speaking at a joint news conference, evoked a moral, economic, and technological imperative "to act now on climate change."

"On the 11 of December [when the conference closes] I want to be able to pronounce six simple words that will be the outcome of unprecedented efforts," Fabius said: "The Paris agreement has been approved."

Fabius and Hollande have traveled the world this year and used France's diplomatic weight to try to rally international support for a tough and binding deal.

Obama has spent more than a year laying the foundation for the summit, coaxing leaders from the major developing countries and elsewhere to make unprecedented pledges to limit greenhouse-gas emissions, protect forests, and undertake formidable new renewable energy projects.

"This is an existential issue for humanity, and his leadership will be appreciated and rewarded by history," Nigel Purvis - founding president of Climate Advisers, a Washington-based consultancy, and a former State Department treaty lawyer - said of the president.

In many ways, the Paris summit, known formally as the 21st U.N. Conference of the Parties (COP21), is already a success. More than 160 countries have put forward climate action plans, and eight of the largest of those economies have pledged collectively to double their renewable energy supply by 2030, according to the World Resources Institute.

The last global climate treaty, the 1997 Kyoto Protocol, required only rich countries to reduce emissions and the U.S., the world's biggest emitter, didn't take part.

Amid the tightened security, a big march by environmental activists was canceled. Activists are still planning other small actions around France and other countries. Greenpeace anchored a hot air balloon next to the Eiffel Tower on Saturday bearing the words "rise up for renewables."

This article contains information from the Washington Post.