"Every year, we issue hundreds of improvements to our algorithms to ensure they surface high-quality content in response to users' queries", Google said.
Google is immensely secretive about how it ranks search results and news stories, and is attempting to personalise its Google News service towards its users' preferences.
"Illegal?" he speculated, going on to accuse Google of "controlling what we can & cannot see".
Dorsey will also testify during the Senate Intelligence Committee's hearing that day on how foreign governments have run misinformation campaigns on American tech platforms such as Facebook, Twitter, YouTube and Google Plus.
He threatened that the situation "will be addressed".
Accusations that Google tampers with search results are not new or uncommon.
National Economic Council Director Larry Kudlow responded to a question on whether there needs to be regulation for Google by saying, "We're taking a look at it".
The PJ Media article that led to Trump's claim turned this into a conspiracy in part by defining nearly all major national news outlets in the United States as on the left, compared to a number of smaller, opinionated and even conspiratorial sites on the right.
Google denied using political viewpoints to shape its search results.
"I told you so!" But he concluded, "they have it RIGGED, for me & others, so that nearly all stories & news is BAD".
Hmm... Googling "Trump news", here's a screenshot of the results.
The claims appeared to be based on a report from the Trump-friendly news site PJ Media which relied on an analysis chart by conservative news host Sharyl Attkisson that categorized major news outlets such as the New York Times, CBS and CNN as "left wing". Google also is expected to send a senior executive.
The US president said the existing system is biased in favour of stories from leftwing news outlets and suggested tech companies were trying to hide positive stories about his administration. The top story is from Fox News, and there are now two mentions of Trump's complaints about Google searches.