Border Patrol agents are "the most assaulted law enforcement personnel in the country," according to the new Border Patrol chief, who warned Congress Tuesday that the agency is distracted from its national security mission by the continuing arrival of unaccompanied minors on the southern border.

"I've learned that the United States Border Patrol agents are among the most assaulted law enforcement personnel in the country," Mark Morgan, the new chief of the Border Patrol, told a House Homeland Security subcommittee panel on Tuesday. "There have been 7,542 assaults against agents since 2006 and 30 agents have died in the line of duty since 2003."

Morgan credited the agency with rescuing thousands of illegal immigrants from life-threatening crises on the border, sometimes at great danger to themselves. But he also warned that "humanitarian" tasks are overtaking the actual mission of the agency, and have the potential to weaken border security.

"What we're being asked to do right now, I think you could phrase it a little bit, is a humanitarian mission," Morgan said. The chief described a moment this summer when he saw a six-year-old girl approach a Border Patrol checkpoint with her 11-year-old brother, having been smuggled to the border from Honduras.

"Now, personally, I wanted to take that little girl home with me ... but as a chief of the United States Border Patrol — which, I think we have a national security interest in this country, we have a law enforcement threat in this country — I think, when I look at that six-year-old, she's not a national security threat or a law enforcement threat," Morgan said.

"I think there needs to be discussion, and I'm asking questions," he continued. "What are some alternatives that we could do instead of taking agents that have been trained, that have a national security mission, that should be on the front line? I'm taking them off that front line a lot to process a six-year-old and an 11-year-old as part of the humanitarian mission."