President Donald Trump on Sunday spoke with “more than two dozen” grocery store and supply chain executives and thanked them for their work as people flock to stores to stockpile on supplies over fears surrounding the spread of coronavirus.

Though the White House said it is unnecessary for Americans to hoard daily supplies, the president told the store executives that stocked shelves with needed items will help Americans feel “safe and calm.”

Keeping shelves stocked and meeting the public’s demand has become an increasingly difficult task for supply chain stores, though. Major grocery stores like Kroger and Publix announced on Sunday that they are changing their store hours to better meet demand.

“Publix will continue to focus on keeping our associates healthy – and our stores open and stocked – to serve and support all our communities,” Todd Jones, Publix CEO, said in a statement regarding the chain closing earlier in order to properly clean and stock.

Videos from US stores in the midst of the coronavirus outbreak show the effects panic buying is having on both consumers and workers.

Some videos show customers taking supplies like paper towels straight off of pallets before they are even stocked.

Others show lines of people ready with their carts waiting outside before stores even open.