Congressional Republicans appear poised to hand President Trump a stinging rebuke of his Turkey and Syria policy when lawmakers return to Washington this week.

President Donald Trump’s new national security adviser, Robert O’Brien, said on Thursday he plans to reduce the size of the National Security Council by about a third in coming months and limit the NSC’s role to gathering options for Trump rather than directing foreign policy.

Former vice president Joe Biden made his most direct call for President Trump’s impeachment Wednesday, hours after Trump said the Democratic-led inquiry should be terminated “for the good of the Country,” claiming it was tainted with political bias.

The White House said Tuesday that it will not cooperate with House Democrats’ impeachment inquiry, ratcheting up tensions between the legislative and executive branches amid an outcry from Democrats that the Trump administration is stonewalling their investigations.

The White House’s decision to block the release of nearly $400 million in aid to Ukraine for more than two months offers a potentially fertile paper trail that House Democrats believe could bolster their case for impeachment against President Donald Trump, congressional sources and former U.S. officials told NBC News.