US President Donald Trump said Sunday it was time to work "constructively" with Russia, saying his counterpart Vladimir Putin had "vehemently denied" meddling in the 2016 election.

"I strongly pressed President Putin twice about Russian meddling in our election," Trump tweeted early Sunday after returning from a four-day trip to Europe where he met Putin for the first time. "He vehemently denied it. I've already given my opinion....."

"Now it is time to move forward in working constructively with Russia!"