Special counsel Robert Mueller has indicted 12 Russian military officials for federal crimes during the 2016 election, including hacking into Democratic emails and servers, including servers run by Hillary Clinton’s campaign.

The move was announced by Deputy Attorney General Rod Rosenstein, just days before President Trump will meet with Russian President Vladimir Putin, when he is expected to press Putin again to explain the U.S. argument that Russia meddled in the U.S. election. It’s likely to boost Democrats who have argued for more than a year that Russia was trying to help get Trump elected, in the face of counterclaims from some Republicans that Democrats leaned on this complaint to explain Clinton’s loss to Trump.