The New York Times shared reports from several GOP Senators that President Trump repeatedly pressured elected officials to end investigations into Russian meddling and Trump campaign officials’ contact with Russians during the course of the 2016 Presidential campaign:

“… Mr. Trump made several calls to senators without senior staff present, according to one West Wing official. According to senators and other Republicans familiar with the conversations, Mr. Trump would begin the talks on a different topic but eventually drift toward the Russia investigation.

“In conversations with Mr. McConnell and Senator Bob Corker, the Tennessee Republican who is chairman of the Senate Foreign Relations Committee, Mr. Trump voiced sharp anger that congressional Republicans were not helping lift the cloud of suspicion over Russia, the senators told political allies. The Times reported in August that the president had complained to Mr. McConnell that he was failing to shield Mr. Trump from an ongoing Senate inquiry.”

For more information:
https://www.nytimes.com/2017/11/30/us/politics/trump-russia-senate-intel.html
https://www.reuters.com/article/us-usa-trump-russia-congress/trump-urged-senate-republicans-to-drop-panels-russia-probe-nyt-idUSKBN1DV3JT