The whistle-blowing website Wikileaks says it is releasing more than two million emails from Syrian political figures, ministries and corporations.
"Ground-breaking" news stories derived from the "Syria files" will be published over the next two months, Wikileaks said.
Its founder Julian Assange was quoted as saying the material was embarrassing - not only to Syria but its opponents.
The emails are said to date from August 2006 to March 2012.
Syrian authorities have been fighting an internal rebellion for some 16 months. Some 15,800 people have died, activists say.
Emails from the Syrian ministries of presidential affairs, foreign affairs, finance, information, transport and culture are all represented among the data to be released, Sarah Harrison from Wikileaks told reporters in London.
"The range of information extends from the intimate correspondence of the most senior [governing] Baath party figures to records of financial transfers sent from Syrian ministries to other nations," she said.
Mr Assange remains in the Ecuadorean embassy in London, where he is trying to avoid extradition to Sweden over accusations of rape and sexual assault.
But Ms Harrison quoted him as saying that this material "helps us not merely to criticise one group or another, but to understand their interests, actions and thoughts. It is only through understanding this conflict that we can hope to resolve it."
Some of the 2,434,899 emails would reveal, Wikileaks promises, "how the West and Western companies say one thing and do another".
News stories based on the emails will be published by news providers including US news agency Associated Press, Spain's Publico.es and Egypt's al-Masry al-Youm.
Some stories which have already appeared seem to concern communications between Syrian representatives and Western suppliers of equipment that could be used for military purposes.