Washington (CNN) President Donald Trump's former personal lawyer and fixer Michael Cohen said under oath Wednesday that he had never traveled to Prague to collude with Russian officials in 2016, denying a key claim of the infamous "dossier" that alleged a conspiracy between Trump and the Kremlin.

His comments during a marathon House Oversight Committee hearing were his first public denial under oath, meaning he could be prosecuted for perjury if he was not telling the truth.

"I've never been to Prague. ... I've never been to the Czech Republic," Cohen told lawmakers.

Cohen has denied the allegation from the very beginning. CNN did not publish the unverified intelligence memos compiled by a retired British spy but was first to report in January 2017 that the documents were being circulated among US intelligence agencies.

The dossier said Cohen had traveled to Prague during summer 2016 and struck a corrupt bargain with Russians, agreeing to coordinate with their efforts to help Trump win the election.

Read More