The homeland security secretary on Sunday defended plans to hire thousands of additional immigration and border-control agents, saying the Trump administration’s lower bar on criminal behavior by undocumented immigrants merits a larger force.

In an interview on NBC’s “Meet the Press,” DHS chief John Kelly dismissed the idea that he’s creating a “deportation force” and noted that U.S. law says people here illegally should leave or be deported.

The Trump administration is focused on criminals, mainly with multiple convictions, he said, but the emphasis can be on lesser types of offenses than was the case under President Barack Obama.

The DHS wants to hire 10,000 additional immigration and customs-enforcement officials and 5,000 more border-security agents. It also plans to expand the number of detention beds to house undocumented immigrants, according to internal documents obtained last week by The Washington Post.

“The definition of criminal has not changed, but where on the spectrum of criminality we operate has changed,” Kelly said on his first appearance on a Sunday talk show since taking over the agency in January, according to a transcript provided by the network.

Asked to provide an example, Kelly cited “multiple” offenses of driving under the influence of alcohol but added that it’s possible a single incident could trigger removal. “Even a single DUI, depending on other aspects, would get you into the system,” he said.

Kelly’s comments come as Congress prepares to resume debate on the administration’s policies on immigration enforcement and plans to build a wall on the U.S.-Mexico border. Lawmakers this month will consider a broad spending bill funding agencies for the remainder of this fiscal year that could include border-security funds. If Congress doesn’t act, a partial government shutdown would begin on April 29.

Congress will then turn to next fiscal year’s budget request from the Trump administration, which proposes deep cuts to programs for education and the environment, among others, in part to offset the expense of more immigration enforcement and border-control measures.

Until now, DHS’s activities have been guided by two executive orders Trump signed in January to boost deportations and border security, which also expanded the pool of undocumented immigrants viewed as a priority for removal.

Kelly said it will be up to Congress to help sort out how to treat the estimated 11 million undocumented immigrants already in the U.S., including the so-called “Dream Act” children brought illegally into the country by their parents or guardians.

Obama shielded 750,000 young undocumented immigrants from deportation with a 2012 executive order. The new administration’s plans remain unclear, although President Donald Trump has suggested he wants to find a solution that could let them stay.

“It’s very complicated,” Kelly said of the range of undocumented immigrants. “There are people who came here as children. There are people here who came here illegally many years ago and have married local men and women and had children.”

Kelly said one of the biggest challenges is people who overstay their visas. Such individuals were the target of raids in February affecting almost 700 people in California, Texas, New York and other states, 75 percent of whom DHS said were criminals.

“It’s time consuming, but at the end of the day they came here with a promise to leave, and we have to track them down if they’re still in the country and put them in the proceedings to deport them,” he said.

Kelly said as the agency expands its border-patrol staffing, he advocates curtailing the use of polygraph tests. Those “lie detector” tests are used in part to identify potential employees who may be susceptible to bribes by, for example, drug cartels. Polygraph tests “take a long time” and are “expensive,” Kelly said.

He noted some instances, such as new hires coming from the military, who may have already been subjected to the tests. The backgrounds of potential DHS agents is “vetted extensively,” he said.