Philip Reeker, the acting assistant secretary of state for European and Eurasian affairs, told House impeachment investigators Saturday that top State Department officials overruled his attempted defense of Marie Yovanovitch, the former U.S. ambassador to Ukraine, the Wall Street Journal reports.

The big picture: The House Intelligence Committee subpoenaed Reeker after the State Department directed him not to attend his Saturday deposition. Reeker is one of several Trump administration officials to testify that he was disturbed by Rudy Giuliani's involvement in Ukraine policy and by the State Department leadership's lack of support for Yovanovitch.

Context: President Trump ordered Yovanovitch's removal in March, after Giuliani, the president's personal lawyer, argued that she was talking badly about the president and was obstructing efforts to persuade Kiev to investigate former Vice President Joe Biden and his son Hunter.

Around the same time, Reeker was named to his current role. He testified that he endorsed efforts by some officials in the department to issue statements supporting Yovanovitch, but the statements were blocked from being released, AP reports.

Reeker said he also became troubled during a White House meeting in which Laura Cooper, deputy assistant secretary of defense for Russia, Ukraine and Eurasia, raised concern over the freezing of congressionally approved Ukraine aid.

Go deeper: EU ambassador told House panels Trump's Ukraine action was quid pro quo