A former President Barack Obama official slammed ICE agents, saying "they do not have the training or skillset" to conduct law enforcement operations in cities.

As ICE tactics grow more violent, concerns and criticism are mounting. In an interview with NPR, Gil Kerlikowske, the former commissioner of U.S. Customs and Border Protection during the Obama administration, said ICE officers are not trained or prepared to handle what is asked of them.

"They do not have the training or skillset or experience to police an urban environment," Kerlikowske said. He was also the Seattle police chief and Buffalo, New York, police commissioner.

He pointed to strategies used to police cities and urban areas that focus on "de-escalation, trust and public cooperation."

The show of force — tackling, using projectiles and gunfire — is something most Americans do not approve of, according to a recent New York Times and Siena University survey.

The show of force federal agents are using in Chicago and elsewhere is unnecessary, Kerlikowske said.

"These are tactics and strategies that are clearly not needed to be able to do their job," Kerlikowske said. "I couldn't be more disappointed."

"These are just the tip of the iceberg," Fred Tsao, senior policy counsel at the Illinois Coalition for Immigrant and Refugee Rights, told NPR. "People being tackled, people getting pepper sprayed or tear gassed. We've seen people getting threatened. And we've seen at least two incidents involving gunfire."

The Department of Homeland Security, which includes ICE, has principles that include "de-escalation" and "respect for human life." But critics call out the recent examples of use of force as not falling in line with these philosophies, and that in the use of force, there must be a valid threat for it to be constitutional. And, the police response must be proportional to the danger of the situation, NPR reports.

"This administration overall seems more interested in heightening the tensions instead of trying to ramp them down," Tsao said.