US Defense Secretary Ash Carter said on Tuesday that the United States' response so far to Russia orchestrating hacks during the 2016 presidential campaign was just the start.
"Some responses have been made. I think you should regard that as a start and not the end," Carter said during a news briefing at the Pentagon alongside the chairman of the Joint Chiefs of Staff, Marine General Joseph Dunford.
Last month, President Barack Obama ordered the expulsion of 35 Russian suspected spies and imposed sanctions on two intelligence agencies over their involvement in hacking US political groups in the 2016 presidential election.
The Kremlin has said the US hacking allegations are "reminiscent of a witch-hunt."