White House press secretary Sarah Sanders defended a top aide to President Trump on Monday amid speculation that the staffer's views on immigration had caused policy talks to stall.

"I think that's a sad and desperate attempt by a few people trying to tarnish a staffer," Sanders told reporters at the White House.

Stephen Miller, Trump's top policy adviser, has been accused of attempting to steer immigration negotiations in a hardline direction as the White House and Congress scramble to reach both an immigration deal and a funding agreement that could reopen the government, which shut down on Friday evening.

"Look, Stephen is not here to push his agenda, he's here to push the president's agenda, like everybody in this building," Sanders said.

Sen. Lindsey Graham, R-S.C., said Sunday, "Every time we have a proposal it is only yanked back by staff members. As long as Stephen Miller is in charge of negotiating immigration, we're going nowhere." he also called the senior aide an "outlier" on immigration policy.

Sanders pushed back specifically on Graham's comments earlier Monday, saying during an interview with Fox News that she found Graham's attacks on Miller and his refusal to align with the White House on immigration policy "sad" and "almost appalling."

White House officials doubled down Monday on their position that Congress should not resume immigration talks until the government reopens.