Still gripped by shock and grief, Paris will play host to a long-awaited U.N. climate conference under tragic circumstances that none could have foreseen.

But delegates to the two-week talks starting Monday insist they won't let the Nov. 13 attacks that killed 130 people in the French capital distract them from the task at hand: crafting a landmark deal to fight global warming.

If anything, some say, the bloodshed could make countries more determined to reach a deal to address a problem that's widely seen as a factor that contributes to conflict.

"There may be even more awareness of how important it is to address climate change, given the impact of climate change on the stability of countries," said Dutch climate envoy Michel Rentenaar.

The French organizers say more than 140 leaders including presidents Barack Obama of the U.S., Vladimir Putin of Russia and Xi Jinping of China have confirmed they're attending the start of the conference.

The stepped-up security measures in Paris — a state of emergency throughout France has been extended for three months — mean that shuttling them around the city will be a major logistics challenge.

Citing security concerns, French authorities have stopped several events that were scheduled to take place outside the conference center, including a big march that environmentalists had planned for Sunday.

The negotiations themselves, however, are set to go ahead as planned amid tight security in the hermetically sealed conference center in Le Bourget, just north of Paris.

Seyni Nafo, the spokesman for the African Group of countries in the climate talks, said "the main variable" is whether French President Francois Hollande can find the time and energy to devote himself fully to the climate talks, given his focus on terrorism and security.

"Other than this I suspect the talks will remain mostly on course," Nafo said.

A top French official, speaking on condition of anonymity because he was not allowed to discuss the issue publicly, said Hollande "remains totally committed to this event and we are now conciliating it with an extraordinarily busy schedule."

Hollande notably maintained all his climate-related appointments last week, including a meeting with some African leaders on Tuesday and a speech to French farmers on Thursday.

This week, he was due to attend several climate-related events despite trips to Washington and Moscow: a France-Oceania summit on Thursday, a meeting with non-governmental groups following the climate negotiations on Saturday, and meetings with U.N. Secretary-General Ban Ki-moon and President Xi on Sunday.

"What powerful rebuke to the terrorists it will be when the world stands as one and shows that we will not be deterred from building a better future for our children," Obama said on Tuesday, with Hollande at his side.

The goal of the Paris conference is for governments to adopt a deal that for the first time would require all countries to take action to fight climate change.

Countries on the front line, such as small island states that could vanish amid rising seas, were worried that the Paris attacks would become a distraction for Western countries in particular. However, they've been reassured by the number of leaders, including Obama, who quickly reaffirmed their plans to attend the U.N. conference, said Jeffrey Waheed, the Maldives' deputy permanent secretary to the United Nations.

"The fact that this is on the forefront of everyone's mind is a positive sign," Waheed said. "World leaders are used to handling multiple issues. And this is an issue of peace and security in the long term."

Researchers and military officials have long stressed the link between climate change and security. The Pentagon noted in a report last year that climate impacts could exacerbate challenges to stability such as infectious diseases and poverty.

Some researchers have even drawn a connection between climate change and the Syrian conflict, saying an extended drought led to social unrest that triggered an uprising against authoritarian President Bashar Assad. The ensuing civil war has forced millions of Syrians to flee the country and fueled the rise of extremist groups like the Islamic State, which claimed responsibility for the gun and bomb massacres in Paris.

With demonstrations in Paris banned, climate activists are planning over 2,000 events across 150 countries this weekend, demanding that negotiators pave the way for a transition from fossil fuels to renewable sources of energy like wind and solar power.

A limited number of activists accredited to the conference will be urging negotiators in the hallways to look beyond their short-term national interests and come together for a common plan for the planet's future.

"Since the climate summit will take place in an atmosphere of war," said Mohamed Adow of Christian Aid, "we hope world leaders will use it to show the world what peaceful global cooperation looks like to protect our shared humanity."

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Ritter reported from Stockholm. AP Science Writer Seth Borenstein in Washington contributed to this report.