The Kremlin has challenged the authenticity of leaked e-mails purportedly from the inbox of presidential aide Vladislav Surkov that appear to show the Russian government's coordination with separatists in eastern Ukraine.
In comments relayed by state-run TASS and other Russian news agencies on October 26, Kremlin spokesman Dmitry Peskov did not explicitly state that e-mails published by the Ukrainian hacker group CyberHunta on October 25 were not genuine.
But he appeared to cast doubt on the authenticity of the leaked documents, saying that Surkov, a longtime adviser to President Vladimir Putin, "doesn't use electronic mail."
"Therefore, someone must have sweated quite a bit to compose this document," Peskov said, though he did not clarify specifically which "document" he was talking about.
"I can tell you: This is not him," he said, referring to Surkov.
The cache of e-mails published by CyberHunta begins in September 2013 and runs through November 2014. That period covers Moscow's annexation of Ukraine's Crimean Peninsula in March 2014 and the subsequent war between Russia-backed separatists and Kyiv's forces in eastern Ukraine.
Russia has consistently denied accusations by Kyiv and Western governments that it is providing the separatists with troops, weapons, and other backing in the conflict, which the UN says has killed more than 9,600 people, despite significant evidence of such support.
Several documents contained in the leak suggest Surkov was a Kremlin point man in dealing with the separatists. These include one purportedly sent from the office of Russian tycoon Konstantin Malofeyev, who is believed to have bankrolled much of the separatist movement in Ukraine.
That PDF file, allegedly sent in an e-mail dated May 12, 2014, features a list of "candidates" for leadership posts in separatist-controlled areas of Ukraine's eastern Donetsk region. The list of names includes Denis Pushilin, the leader of separatists in the region, and former separatist commander Igor Girkin, also known as Strelkov.
When separatist leadership posts were announced three days later, several of the self-styled officials were granted the same titles recommended in the document purportedly sent to Surkov from Malofeyev's office.
Like Surkov, Malofeyev has been hit with U.S. and EU sanctions for his alleged role in the conflict.
The e-mail dump also appears to show Surkov's office directly interacting with the separatist leadership. One communication dated June 14, 2014, appears to have been sent from Pushilin and includes attachments listing names of those killed or wounded in the conflict during a two-week period.
Peskov's claim that Surkov does not use e-mail is not contradicted by the cache leaked by CyberHunta. A large number of the communications suggest they were handled by Surkov's underlings and include requests to pass the e-mails on to Surkov.
Oleksandr Tkachuk, chief of staff for the Ukrainian Security Service (SBU), told RFE/RL on October 26 that his agency managed "to authenticate a number of documents in the release" but conceded that "there is not enough evidence to believe the entire [collection] of documents found in Surkov's e-mails is actually original or authentic."
"In order to confirm their authenticity, we need access to the e-mail account and original downloaded e-mails from the account," Tkachuk said.
A day before CyberHunta published the cache of e-mails purportedly from Surkov's office, the group claimed that it hacked Surkov's e-mail account and found documents with plans for the "destabilization of the political situation in Ukraine" between November 2016 and March 2017 with the goal of forcing Kyiv "to hold early parliamentary and presidential elections."
Following that claim, Peskov said on October 25 that Surkov was "a talented man" and that "many allegations against him by hackers in Russia and elsewhere are mainly false."
Two sources within Ukraine's security apparatus told RFE/RL they do not believe the alleged destabilization plan is authentic, and Tkachuk said Ukrainian authorities had not determined whether it is real.
"The PDF files do look strange. That's why we would like to see the originals," he said. "Then we could do forensic analysis and make a final conclusion."
Surkov previously served as a key adviser to Putin on domestic political matters and currently advises the Russian president on the West-leaning former Soviet countries of Ukraine, Moldova, and Georgia.
With reporting by Christopher Miller in Kyiv, TASS, UNIAN, and Interfax