Senate Minority Leader Chuck Schumer, D-N.Y., said Wednesday the resignation of Attorney General Jeff Sessions is "very suspect" and hopes that it is not a "prelude" to ending the Mueller investigation.

Schumer argued that ending the investigation would create a constitutional crisis, adding that he hopes Trump heeds his warning. News of Sessions' dismissal came out during Schumer's press conference on Tuesday's elections.

"Oh," said a visibly surprised Schumer when informed of the news. "I just heard the news, but I'd say this: Protecting Mueller and his investigation is paramount. It would create a constitutional crisis if this were a prelude to ending or greatly limiting the Mueller investigation, and I hope President Trump and those he listens to will refrain from that."

"I find the timing very suspect," Schumer said later. "Our paramount view is that any attorney general, be it this one or another one, should not be able to interfere with the Mueller investigation in any way.

"They should not be able to end it. They should not be able to limit it. They should not be able to interfere with Mueller going forward and doing what he thinks is the right thing, and that will help guide us as we go through this process," he said.

[More: Humiliating details of Trump's firing of Sessions emerge]

Trump made the announcement on Twitter midway through the press conference, adding that Matthew Whitaker, Sessions' chief of staff, will replace him as acting attorney general.

Schumer did not touch on any possible permanent solution to replace Sessions. The president announced that a replacement will be revealed at a later date.

"It wouldn't matter if they picked up a couple of seats because nominees just need 51 votes," Schumer said of Tuesday's impact on Sessions' replacement. "We would hope, if there's a constitutional crisis, that our Republican colleagues would join us in thwarting the president from creating that crisis. We'll see."