Democratic presidential hopeful Cory Booker admitted Tuesday that there is an issue with illegal immigration on the southern border — and urged fellow Democrats not to deny the severity of the situation.

Booker, a senator from New Jersey, made the statement at a campaign event in Sergeant Bluff, Iowa, according to video of the event.

“We do have a problem at the southern border,” Booker said. “Democrats should not deny that we [do]. Nations should have borders, borders should be respected.”

Booker, however, went on to criticize President Trump’s call to build a wall on the the southern border to stem the flow of Central American migrants who come across hoping to gain asylum in the U.S.

“My beef with this president is that number one, his technologies don’t work. I’ve gone down to the border, I’ve hung out with [Customs and Border Protection]” Booker said. “They’re like, ‘there’s no way we need a wall coast to coast.’”

“We have a time now where you can use sensors and technologies and drones and a lot more to protect the border, which is what we should do,” he added.