Lt. Col. Alexander Vindman’s Friday ouster was just the beginning.

National security adviser Robert O’Brien is set to overhaul the NSC staff as early as next week, according to a CNN report Saturday.

Two sources familiar with the matter told CNN that O’Brien was expected to oust around a dozen officials as part of an effort to streamline the NSC.

Although O’Brien has already been downsizing the NSC by attrition and transferring staffers detailed from other departments to return to their home agencies earlier than planned, a source told CNN that the final phase will include more direct firings and cuts.

Last Tuesday, O’Brien described the NSC staff size as “bloated” to Fox News’ Laura Ingraham and that when he came to the NSC he had planned to “drastically downsize it.” O’Brien added that the NSC had “ballooned up” to 236 policy professionals in the Obama administration compared to about 100 during the Bush administration, but that in “another week or two, I think we’ll have met our goal.”

CNN’s report comes a day after Vindman, the NSC’s top Ukraine expert who testified in the House impeachment inquiry, was fired along with this twin brother Lt. Col. Yevgeny Vindman.