'This Week' Transcript: Sec. Jeh Johnson

— -- This is a rush transcript. It may contain errors and will be updated.

UNIDENTIFIED MALE: Starting right now on ABC'S THIS WEEK, ISIS in America -- inside the urgent new FBI warnings -- jihadists here in the homeland ready to strike.

Plus, military bases around the country now on high alert. Our exclusive live interview with Homeland Security Secretary Jeh Johnson.

2016 shakeup -- why these long shot candidates are making big waves.

A Texas-sized conspiracy theory goes viral -- why some think martial law is on the way in the Lone Star State. The surprising response from the state's governor.

And Deflate-gate takedown -- what will happen to Super bowl hero, Tom Brady?

From ABC News, THIS WEEK WITH GEORGE STEPHANOPOULOS begins now.

MARTHA RADDATZ, HOST: Good morning on this Mother's Day.

I'm Martha Raddatz.

Great to have you with us.

We start off with those dramatic new warnings from the FBI that hundreds, maybe thousands of ISIS followers inside the U.S. are being urged to kill Americans.

Military bases nationwide increasing security -- our exclusive live interview with the Homeland Security secretary just moments away.

First, the very latest on these extraordinary warnings from senior justice correspondent, Pierre Thomas -- good morning, Pierre.

PIERRE THOMAS, ABC NEWS CORRESPONDENT: Good morning, Martha.

And that urgent Friday conference call, the FBI director and Homeland Security secretary met with thousands of law enforcement officials from across the country to warn them about an unprecedented social media campaign by ISIS that is reaching Americans in every state.

(BEGIN VIDEOTAPE)

THOMAS (voice-over): The meeting of top law enforcement officials came on the heels of Sunday's shootout in Texas by two men believed to be ISIS supporters communicating with the group via social media.

UNIDENTIFIED MALE: Police officers that were nearby saw what was happening and engaged the two men and shot and killed them there at the scene.

THOMAS: FBI Director Comey told reporters he believes ISIS has a large social media following in the U.S., numbering in the hundreds, if not the thousands. Those followers every day are being urged to join the Islamic State and Comey says told to kill, kill, kill wherever they are.

In response to Comey's concerns about ISIS' use of social media, the U.S. military is making security changes at bases across the country.

Here's ABC's Matt Gutman.

MATT GUTMAN, ABC NEWS CORRESPONDENT: This is just the U.S. Coast Guard installation here in Miami. And like all U.S. military installations worldwide, security here is heightened.

Now, this wasn't just prompted by that FBI warning. This also has to do with ISIS supporters posting online the names, pictures and addresses of 100 U.S. servicemen and women.

THOMAS: In a number of recent cases, the military has been a target right here at home. This spring, a member of the Illinois National Guard was charged with supporting ISIS and allegedly planning an attack on his fellow soldiers.

In the last two years, the FBI has stopped more than 50 Americans trying to join ISIS or support the group overseas.

UNIDENTIFIED MALE: They are shooting out into the ethospehere thousands and thousands of messages a day, over 90,000 messages a day.

THOMAS: ISIS has been waging a secret war, a social media campaign unlike anything U.S. law enforcement has seen before. Their supporters mimic the popular Grand Theft Auto video game, selling murder and mayhem as fun.

(VIDEO CLIP)

THOMAS: ISIS radicals use hip-hop to lure young recruits.

UNIDENTIFIED MALE: This is Madison Avenue meets documentary filmmaking meets news channel with P.R. sensibilities and a marketing value.

THOMAS: Some in Congress believe the U.S. online response to the ISIS social media onslaught has been weak.

UNIDENTIFIED MALE: Look at their fancy means compared to what we're not doing.

(END VIDEO TAPE)

THOMAS: The FBI has hundreds of investigations of suspected home grown radicals, many involving ISIS -- Martha.

RADDATZ: Thanks very much, Pierre.

RADDATZ: With us now, our exclusive guest, Homeland Security Secretary Jeh Johnson. Good morning, Mr. Secretary, thanks for joining us.

JOHNSON: Good morning, Martha.

RADDATZ: We have been talking about the ISIS social media campaign for well over a year, and yet the urgency this week coming from the FBI was quite extraordinary.

JOHNSON: Well, let me begin with this. This weekend, we’re celebrating the 70th anniversary of the defeat of Nazi Germany. Next week, here in Washington, we celebrate National Police Week, in honor of our fallen heroes in law enforcement. We encourage the public to attend these events. There were thousands of people on the National Mall last week celebrating VE day. We want the public to be vigilant, to be aware, but we encourage people to go to public events, sporting events. But we’re very definitely in a new environment, because of ISIL’s effective use of social media, the Internet, which has the ability to reach into the homeland and possibly inspire others. And so our government and our state and local law enforcement are having to do a number of things to address that, which is why FBI director Comey and I spend a lot of time these days talking to police chiefs, sheriffs around the country. We did that in a video teleconference just on Friday.

RADDATZ: Which was quite extraordinary in itself. You had really thousands of local law enforcement. Are homegrown jihadists ready to strike here in the U.S.?

JOHNSON: We have these types of bulletins, video teleconferences on a regular basis. Director Comey and I thought it be appropriate that we personally participate. And your question reveals the new environment we’re in, in that because of the use of the Internet, we could have little or no notice in advance of an independent actor attempting to strike. And so that’s why law enforcement at the local level needs to be ever more vigilant and we are constantly reminding them to do that.

RADDATZ: It is the current structure of Homeland Security, the FBI really prepared for this kind of threat? Or are we going back and saying, look, we’ve done it all right before, we’ll do the same thing? There is no command and control, really, on these home grown jihadists. There might be.

JOHNSON: Well, that’s correct. Every event, every attempted event, is very definitely a lesson learned. But since 9/11, we’ve come a long way in our ability to interface with state and local law enforcement. Just on my watch in the last 16 months, we’ve had to ramp up our communications with state and local law enforcement because of the manner in which the global terrorist threat is evolving. And the FBI and my department work every day together to get information out to law enforcement on the local level.

RADDATZ: Let me go back to some of these statements by Director Comey. It’s like they’re saying kill, kill, kill all day long. There is nothing different between inspired and directed. If you can’t travel, they’re saying kill where you are. Are you as concerned as Director Comey? Would you say this is the urgency that we should be concerned about? Kill, kill, kill?