The US National Security Agency spied on the communications conducted by other governments before and during the 2009 United Nations climate negotiations conference held in Copenhagen, according to a report based on documents leaked by Edward Snowden.

A “top secret” document published by the Huffington Post this week reveals that the NSA was keeping tabs on how other countries were communicating before the conference and that the intelligence agency planned to keep its operations running through the meeting.

The document was published on an internal NSA site on the first day of the Denmark conference, December 7, 2009, and stated that “analysts here at NSA, as well as our Second Party partners, will continue to provide policymakers with unique, timely, and valuable insights into key countries’ preparations and goals for the conference, as well as the deliberation within countries on climate change policies and negotiation strategies.”

The mention of “Second Party partners” is a reference to the Five Eyes group of nations that the US shares intelligence with, a group that includes the United Kingdom, Canada, Australia, and New Zealand.

The Huffington Post reported on the documents Wednesday evening in conjunction with Information, a Danish daily newspaper that also worked with journalist Laura Poitras. The document clearly shows that the NSA sought to gain collect intelligence on negotiating parties’ private meetings throughout the summit.

Nearly 200 countries participated in the 15th Conference of the Parties to the United Nations Framework Convention on Climate Change. The two-week summit was the first of US President Obama’s administration and was expected to end in a major breakthrough regarding the impact of rising greenhouse gas emissions. This meeting was supposed to end in an agreement between the US, China, India, and others with quickly growing emissions on a plan to curb their contribution to climate change.

“While the outcome of the Copenhagen Climate change Conference remains uncertain, signals intelligence will undoubtedly play a significant role in keeping our negotiators as well informed as possible throughout the 2-week event,” the document states.

“[L]eaders and negotiating teams from around the world will undoubtedly be engaging in intense last-minute policy formulating; at the same time, they will be holding sidebar discussions with their counterparts – details of which are of great interest to our policymakers,” the document states before noting that the information would then likely be used to brief top American officials including President Obama and then-Secretary of State Hillary Clinton.

While the document did not include any mention of how the surveillance was conducted, members of the Danish negotiation team did tell Information that US and Chinese delegations were “peculiarly well-informed” about closed-door discussions.

“They simply sat back, just as we had feared they would if they knew about our document,” one source said. “They made no constructive statements. Obviously, if they had known about our plans since the fall of 2009, it was in their interest to simply wait for our draft proposal to be brought to the table at the summit…I was often completely taken aback by what they knew.”