Washington (CNN) President Donald Trump, a week after downplaying Russian interference in US elections, said Tuesday he is "very concerned" that Russia will look to impact the 2018 midterm elections and said he believes Moscow will look to boost Democrats this time.

Trump offered no evidence for his claim that Russia would look to help Democrats win in 2018 beyond claiming he has been tougher on Russia than his predecessors.

"I'm very concerned that Russia will be fighting very hard to have an impact on the upcoming Election. Based on the fact that no President has been tougher on Russia than me, they will be pushing very hard for the Democrats," Trump tweeted Tuesday. "They definitely don't want Trump!"

I'm very concerned that Russia will be fighting very hard to have an impact on the upcoming Election. Based on the fact that no President has been tougher on Russia than me, they will be pushing very hard for the Democrats. They definitely don't want Trump! — Donald J. Trump (@realDonaldTrump) July 24, 2018

Trump's tweet comes a week after he faced blistering criticism from Democrats and Republicans alike for touting Putin's denial of Russian interference in the 2016 election and challenging the US intelligence community's assessment of that interference. Trump partially walked back his comments after returning to the US by saying he misspoke when he said he didn't see why "it would be Russia."

But the next day, Trump replied "no" when asked if he believes Russia is still targeting the US -- with the White House press secretary later claiming he was not responding to that question.

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