Rasmussen Reports is an American polling company which collects, publish and distribute public opinion polling information.
"Without the phony Russia witch hunt, and with all that we have accomplished in the last almost two years (Tax and Regulation Cuts, Judge's, Military, Vets, etc.) my approval rating would be at 75 per cent rather than the 50 per cent just reported by Rasmussen," Trump said in a tweet.
"It's called Presidential Harassment!" he said.
His tweets came amidst investigations by Special Counsel Robert Mueller, a former FBI director, into the allegations of Russian interference in the 2016 presidential elections and collusion with the Trump campaign.
So far, more than 30 people have been charged or pleaded guilty in Mueller's investigation. President Trump's campaign chairman, top campaign aide, former national security advisor and longtime personal attorney are all cooperating in the inquiry, which the president calls a "witch hunt".
(With inputs from agencies.)