By Julia Edwards

WASHINGTON (Reuters) – U.S. Assistant Attorney General John Carlin said on Monday that more than 110 people have been publicly charged in federal court since late 2013 on counts related to the Islamic State militant group that has overrun much of Syria and Iraq.

Carlin said the U.S. Justice Department needs the American public to be more proactive about alerting federal authorities when they witness someone showing support for foreign terrorist organizations, such as Islamic State, in remarks to reporters at the U.S. Justice Department.

In more than 80 percent of the Islamic State cases that have been prosecuted since 2013, someone in the community of the accused person believed they had witnessed the activity for which the person was ultimately charged, according to Carlin. In more than half of those cases, the witnesses did not report anything to law enforcement authorities until after the charges were made.

Many of the Islamic State supporters prosecuted since 2013 have been charged under “material support” statutes that prohibit supporting designated foreign terrorist organizations. No groups based on domestic ideology, such as white supremacists have that designation.

Carlin said he is open to considering whether affiliation with a domestic extremist group could “warrant a special penalty” for people already charged with committing a violent crime.

Simply supporting a domestic group where some of the members have committed crimes, should not be prosecuted, Carlin said, because it “runs into our Constitution and our values.”

“You’re getting close to making illegal ideas,” Carlin said.

The Department of Justice charged 60 people last year with supporting or committing crimes because of their sympathies to Islamic State, the largest annual figure on record. The number arrested this year has been less than last year’s figure.

(Reporting by Julia Edwards; Writing by David Alexander and Julia Harte; Editing by Eric Walsh, Bernard Orr)