WASHINGTON — Kirstjen Nielsen, the homeland security secretary, said on Monday that cyberthreats against the United States were a national security crisis that she described as her top priority — not the situation for which President Trump last month declared a national emergency.
“On top of my list of threats, that many of you can guess, the word ‘cyber’ is circled, highlighted and underlined,” Ms. Nielsen said in a speech outlining her department’s focus in the coming year. “The cyberdomain is a target, a weapon and a threat vector all at the same time.”
Mr. Trump has called the increasing flow of immigrants to the southern border one of the most urgent national security issues threatening the United States. Last week, issuing his first veto against legislation that would have blocked him from diverting Defense Department funds to build a border wall, the president described a recent spike in migrants crossing the border as an “invasion.”
The Department of Homeland Security oversees customs officers and immigration agents who are on the front lines of the Trump administration’s campaign to close the border to illegal immigration.
Ms. Nielsen did dedicate a portion of her speech on Monday to what she called a “humanitarian and security catastrophe” of Central American families traveling to the border. She also noted that the projected number of migrants who may be apprehended at the southern border this month was expected to rise to 100,000, up from 76,000 in February.
But mentions of digital threats were dispersed throughout her approximately 35-minute address to an auditorium of various Department of Homeland Security officials.
Among global jihadists and transnational criminals, Ms. Nielsen listed “cyberthugs and hackers and resurgent nation-state rivals” as an emerging threat to the United States. She asked two cybersecurity officials who helped safeguard the 2018 elections to stand for a round of applause.
Ms. Nielsen also assailed President Vladimir V. Putin of Russia and the Kremlin “for a concerted effort to undermine our elections and our democratic process using cyberenabled means.” And she said the average American citizen or company was “no match” for virtual threats from Russia, China, North Korea and Iran.
“I am more worried about the ability of bad guys to hijack our networks than their ability to hijack our flights,” Ms. Nielsen said. “I am concerned about them holding our infrastructure hostage, stealing our money and secrets, exploiting children online and even hacking our democracy.”
John Cohen, a former acting under secretary for intelligence during the Obama administration, said law enforcement could no longer look at the threats in the digital world and the physical world as separate issues. Extremist groups now circulate videos on the internet to inspire terrorist attacks, and drug traffickers are using the dark web — something Ms. Nielsen also highlighted in her speech.
Mr. Cohen said he remained unclear on how Ms. Nielsen proposed combating cybersecurity threats.
The Department of Homeland Security is “unique in its ability to confront the diverse and serious threats facing this country,” said Mr. Cohen, also a senior adviser at the agency during the George W. Bush administration. “My concern is because this administration has so emphasized border security and immigration enforcement that the department, its other responsibilities, will be underutilized.”
Ms. Nielsen said the department was focused on increasing collaboration with the private sector, citing a summit meeting held in New York last year for industry and government officials. She said she expected the cooperation between various homeland security agencies to improve when the department consolidates at a former mental hospital next month.
She praised the department’s work in defending the integrity of the 2018 midterm elections and said she was confident in her department’s ability to secure the 2020 presidential vote. Ms. Nielsen also said homeland security would continue to pursue prosecutions against foreign entities that hack the American digital infrastructure.
“What worries me, though, is not what these threat actors have done,” Ms. Nielsen said, “but what they have the capability to do.”