DHS Secretary Kirstjen Nielsen said Friday she believes the midterm elections will be the “most secure election in the modern era” but told Fox News in an exclusive interview that “everything is on the table” if others try to meddle with the vote.

In New York City for a cyber security event at the Council on Foreign Relations, Nielsen said the government is in a “tremendously different place” than in 2016, when the Russians attempted to interfere in the presidential election.

"I do think it's safe to stay this will be the most secure election in the modern era,” Nielsen said. “We are in a tremendously different place than we were in 2016 in terms of partnerships with state and locals and everything they have done to secure their infrastructure."

Pressed on whether a cyber response is being readied by the United States if attacked, Nielsen said, "Everything is on the table. I think the president has made it very clear if we are attacked we will defend ourselves so every element of power that we have available to us will be considered in terms of our response."

Nielsen, along with FBI Director Chris Wray and Director of National Intelligence Dan Coats, gave Trump an election security briefing on Thursday. She said the president’s "basic message was elections are the heart of our democracy. It's extraordinarily important that Americans have confidence in them."

Nielsen will oversee a virtual, nationwide "situation room" on election night that tracks cyber threats to voter databases, as well as online efforts using propaganda and disinformation to influence voters' perceptions and decision making.

The National Cybersecurity and Communications Integration Center (NCCIC) and the Department of Homeland Security have implemented monitoring for the midterms that covers about 90 percent of registered voters. Known as Albert sensors, the program flags cyber intruders. More than half of all states have completed vulnerability assessments, DHS says.

The intelligence community recently warned that Russia, China and Iran leverage social media to amplify issues that divide voters. Last cycle, a Russian troll factory masqueraded online as U.S. citizens, officials said, and earlier this year, Beijing sponsored pro-China ads to sway American farmers.

"We continue to see extraordinarily aggressive actions by multiple countries to influence the way Americans think,” she said.

Nielsen warned that foreign governments and hackers may not breach voting systems but they may still exploit election night "to sow confusion, discord and mistrust by placing stories in social media or state sponsored media that something was wrong.”

But, she said, “I think all Americans should wait and not jump to conclusions. We will do the assessment."

Fox News’ Kayla Ewertz contributed to this report.