MOSCOW (AP) — A group of Ukrainian hackers has released thousands of emails from an account used by a senior Kremlin official that appear to show close financial and political ties between Moscow and separatist rebels in Eastern Ukraine.

The cache published by Ukrainian group CyberHunta reveals contacts between President Vladimir Putin's adviser Vladislav Surkov and the pro-Russia rebels fighting Ukrainian forces.

The Ukrainian secret services said Wednesday the emails were real, although they added the files may have been tampered with. Putin's spokesman Dmitry Peskov dismissed the published emails as a sham, saying Wednesday that Surkov doesn't use email.

Russian journalist Svetlana Babaeva told The Associated Press emails from her in the cache were genuine.

Earlier this month, Surkov accompanied Putin to Berlin for talks with European leaders on the Ukrainian crisis.