Washington (CNN) President Donald Trump and House Speaker Nancy Pelosi clashed in two stunning moments at Tuesday night's State of the Union address, when Trump appeared to ignore Pelosi's attempt at a handshake and she later ripped up her copy of his speech after he concluded.

The frosty exchanges came on the eve of the Senate's expected acquittal of Trump in his impeachment trial , which was sparked by House Democrats' investigations of Trump's conduct regarding Ukraine. It's unclear whether Trump avoided Pelosi's handshake on purpose, and a source close to the House speaker told CNN's Dana Bash the decision to tear up the speech wasn't planned but was sparked by her anger at the address.

The moments were unmistakable signs of the deteriorating relationship between the two leaders, who hadn't communicated with each other in months, as well as the increasing partisan rancor in Washington following the five-month impeachment saga and the upcoming 2020 presidential election

A Trump adviser told CNN's Jim Acosta that by apparently ignoring Pelosi the President missed an opportunity to heal a divided nation.

"The country seems very, very divided but I think Trump made a mistake not shaking her hand," the adviser said, while also faulting "the Democrats by being so silent and not clapping on even nonpartisan lines."

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