National security chief: proof of hacking is 'incontrovertible'
US national security adviser HR McMaster acknowledged at the weekend that evidence of Russian interference in the 2016 presidential election is "incontrovertible".
But he said Moscow's campaign to divide the West through subterfuge was failing.
"It's just not working," he said.
The comments, a day after the Justice Department indicted 13 Russians on charges of interference in the election, follow months of efforts by the president to cast doubt on assertions of Moscow's interference.
In a late-night tweet, President Trump hit out at McMaster, saying he "forgot" to mention that the Russians had not impacted the results of the election and that there had been no collusion with his campaign.
Both are frequent Trump talking points that have not been substantiated by intelligence agency conclusions or investigators.
McMaster's comments came at a global security conference to try to rally Western allies against common enemies, offering an olive branch to US partners that have often felt battered and neglected in the age of Trump.
The US, McMaster said, is committed to working with Europe to combat nuclear proliferation, choke off funds for terrorist groups and thwart Russian ambitions.
But the appeal could not hide the deep fissures among Western allies - chief of which was the gap between the United States and its European allies. A day after Germany's defence minister slammed the US for cutting funds for diplomacy, Foreign Minister Sigmar Gabriel suggested the US had abandoned core values.