U.S. President Donald Trump said on Thursday that he will look into Twitter Inc.’s latest "shadow banning" move that impacted key Republicans.

Twitter shares slipped 3.2 per cent, to US$42.79 in early trading in New York.

According to a report Wednesday by Vice News, Twitter is restricting the visibility of Republicans including Republican Party Chairman Ronna McDaniel and GOP members of Congress in an attempt to improve political debate on its service. Democrats haven’t been "shadow banned," the website reported.

A Twitter spokesman said in a statement Thursday that the company doesn’t engage in shadow banning. “We are aware that some accounts are not automatically populating in our search box, and shipping a change to address this. The profiles, Tweets and discussions about these accounts do appear when you search for them.”

Twitter CEO Jack Dorsey responded to the report in a tweet Wednesday. "We have a lot more work to do to earn people’s trust on how we work," he said.

Dorsey highlighted a thread from Twitter’s product head Kayvon Beykpour, who wrote, "To be clear, our behavioral ranking doesn’t make judgments based on political views or the substance of tweets."

He added that the company had recently testified before Congress on the topic.