Transcript for What's Next for US in Fight Against ISIS?
Good afternoon I'm Cecilia -- at ABC news headquarters in New York with a digital special report. US officials are on high alert today over concerns about a possible lone wolf attack here at home in retaliation for US airstrikes against I -- in Iraq. The heightened alert comes as the White House signals it may now expand that fight against I -- One day after the US struck ice -- targets near Iraq's Mosul dam. After the brutal videotaped execution of American journalist James Foley crisis is now threatening to kill more American hostages. Including journalists Stephen sought -- if the US continues its airstrikes. ABC's chief White House correspondent Jonathan Karl is in Martha's Vineyard where the president is winding down his summer vacation. And John joins us now with the latest details John. We -- the president returns home from vacation tomorrow is there any indication of how he's going to move forward in the coming days. We'll see what we know is that the president and his national security team. Are actively looking into options for expanding the air campaign the campaign of airstrikes against crisis. Looking at possible targets inside Syria as you know. Syria is where this group really came to prominence developed its strength. To make its you know progress into Iraq so if you ultimately they're gonna defeat ice this as the chairman of the Joint Chiefs of Staff has said you're gonna need to hit. -- -- targets inside Syria that would be a significant step forward for the president. To be clear he has never ruled -- out that's always been a possibility if there was any sense of an imminent threat. Coming from Syria there's never it's never been ruled out the US would hit targets there. But it would clearly be an expansion all of this field then and of course some would be saying this would be clear mission creep. As well -- and that look overseas though the FBI we know is warning about the possibility of homegrown terrorist threats how serious of a threat. Are we talking about here on the US home France. Walt other clearly taking it seriously that's why you saw the FBI come out of a three page warning on this that said it's important to point out that they. At that very threat warning said that their -- of no credible immediate threat to the homeland nothing specific. Nothing imminent. But that the spooky thing about this Cecilia is the FBI noted did this group and those sympathetic to this group. Could strike quickly and with virtually no notice of a specific concern special concern are US targets overseas which would be the easiest. Offered this group for or against sympathizers -- -- -- hit him hard. Okay BC's Jonathan Karl reporting -- from Martha's Vineyard today thank you very much ABC news is monitoring these developments around the clock. To get updates on these top stories -- them on the ABC news phone apps. And I will have a complete wrap up later on world news. For now I'm Cecilia Vega in New York have a good to.
This transcript has been automatically generated and may not be 100% accurate.