White House senior adviser Kevin Hassett warned Sunday that the outlook for the U.S. economy hard hit by the coronavirus pandemic is a “really grave situation,” and said that unemployment rates could reach levels seen during the Great Depression.

ABC’s “This Week” host George Stephanopoulos asked Hassett whether a “V-shaped,” or short, sharp, recovery, is possible. 

Hassett responded that the U.S.’s economic future will “depend on what happens next.” He predicted “everybody’s gonna pull together” in the next three to four weeks to create a plan to give the country the best chance for a V-shaped recovery.

“But make no mistake, this is a really grave situation George,” he said. “This is the biggest economic shock our economy I think has ever seen.”

“We’re going to be looking at an unemployment rate that approaches rates that I think we saw during the Great Depression,” he added. 

NEW: White House senior adviser Kevin Hassett tells @gstephanopoulos that the economic outlook is a “really grave situation.”

“We’re going to be looking at an unemployment rate that approaches rates that I think we saw during the Great Depression.” https://t.co/vM8WcrQKg0 pic.twitter.com/ds7QtseNqe

— This Week (@ThisWeekABC) April 26, 2020

But he said “another round of really solid legislation” is necessary for the possibility of achieving a V-shaped recovery. 

The White House adviser also expressed concern about the “climbing” national debt with the federal response to the pandemic. 

“So for sure, we need to do still some short run things,” he said. “But I think looking at long-run changes that we can make to things to improve the debt situation – you know, that should be something that is on the table.”

White House senior economic adviser Kevin Hassett warns of “climbing” national debt.

Hassett says “while we’re providing short run stimulus” to states amid the coronavirus pandemic, the U.S. needs to “look at long run changes” to address the rising debt. https://t.co/R0osog596P pic.twitter.com/SHIsYa95ZK

— This Week (@ThisWeekABC) April 26, 2020

Treasury Secretary Steven Mnuchin, meanwhile, forecasted on Sunday that the U.S. would rebound this summer and in the early fall, although other experts have predicted longer timelines. 

“We are putting an unprecedented amount of fiscal relief into the economy,” Mnuchin said “Fox News Sunday.” “You’re seeing trillions of dollars that’s making its way into the economy and I think this is going to have a significant impact.”

At least 26 million people filed for unemployment benefits in five weeks, according to Department of Labor data.