Washington (CNN) State Department Deputy Assistant Secretary George Kent told lawmakers on Tuesday that he had been told by a supervisor to lie low after he raised complaints about Rudy Giuliani's efforts in Ukraine undermining US foreign policy, according to Democratic Rep. Gerry Connolly, a senior member of the House Oversight Committee.

Connolly, a Virginia lawmaker, said Kent described Giuliani's campaign to oust the US ambassador to Ukraine outside of the State Department channels as having "undermined 28 years of US efforts to try to promote the rule of law in Ukraine."

Kent testified behind closed doors on Tuesday before the House Intelligence, Foreign Affairs and Oversight committees as part of the impeachment inquiry into President Donald Trump and Ukraine.

Kent's testimony described how he believed Giuliani's efforts to oust the Ukrainian ambassador and conduct a parallel foreign policy was "wrong" and how Ukraine policy-making in the Trump administration had been consolidated into the hands of a few officials, according to Connolly.

Kent told lawmakers in his role as deputy assistant secretary in the European and Eurasian Bureau, he was responsible for six countries, including Ukraine.