The University of East Anglia said it was checking the authenticity of a batch of e-mails released on the Internet on Tuesday in what appeared to be a carefully-timed attempt to reignite controversy over the science behind climate change.

Negotiators from almost 200 countries meet from November 28 in South Africa for a U.N. climate summit, where only modest steps are expected towards a deal on cutting greenhouse gas emissions, despite warnings from scientists that extreme weather will likely increase as the planet warms.

Documents on a server on Tuesday claimed to have come from the university, whose Climate Action Research unit is considered one of the world's leading institutions on climate science.

Two years ago, a series of e-mails written by climate experts from the university were stolen by unknown hackers and spread quickly across the Internet, just before a U.N. climate summit in Copenhagen. The leaked e-mails contained private correspondence dating back to 1996.

In what became known as Climategate, the e-mails showed scientists made snide comments about climate sceptics and revealed exchanges about how to present data to make the global warming argument look convincing.

Climate sceptics accused the scientists of manipulating data from the Intergovernmental Panel on Climate Change's 2007 fourth assessment report. That report by the U.N. panel of climate scientists forms the basis for policy-making by many governments and decision-makers around the world.

The BBC reported that Tuesday's documents appeared on a Russian server and appeared to argue that combating climate change could create poverty.

The server, http://files.sinwt.ru/download.php?file=25FOIA2011.zip could not be accessed by Reuters at the time of writing.

While we have had only a limited opportunity to look at this latest post of 5,000 e-mails, we have no evidence of a recent breach of our systems, the University of East Anglia said in a statement sent to Reuters.

If genuine, (the sheer volume of material makes it impossible to confirm at present that they are all genuine), these e-mails have the appearance of having been held back after the theft of data and e-mails in 2009 to be released at a time designed to cause maximum disruption to the imminent international climate talks.

This appears to be a carefully-timed attempt to reignite controversy over the science behind climate change when that science has been vindicated by three separate independent inquiries and a number of studies, it added.

Independent inquiries cleared the university of all accusations of fraud and data manipulation but did recommend it change the way it handled requests for information.

Police were not immediately available to comment on whether they will be examining the most recent e-mails.

Following the previous release of e-mails, scientists highlighted by the controversy have been vindicated by independent review, and claims that their science cannot or should not be trusted are entirely unsupported, the university said.

(Reporting by Nina Chestney; Editing by Janet Lawrence)