By Julia Edwards

WASHINGTON (Reuters) - The U.S. Department of Homeland Security will announce on Wednesday $10 million in grants for non-profit organizations and colleges to develop counseling programs and other services to turn people away from violent extremism, according to a senior DHS official.

The official, who spoke to Reuters on the condition of anonymity before the planned announcement, said the department recognizes law enforcement is limited in its ability to intervene before someone becomes radicalized like Omar Mateen, the gunman who killed 49 people in Orlando last month.

After killings by Muslim extremists in San Bernardino, California, Boston and Garland, Texas, DHS officials found family and community members of the perpetrators suspected their intentions but did not know where to turn.

The grants are designed to support mental health clinics, community groups and other places where someone can be referred for help before they come under the radar of law enforcement.

The $10 million was allocated by Congress in December as part of an effort by the Justice Department and DHS to launch a softer, community-based approach to counter extremist messages like those promoted by the Islamic State militant group online.

The program, known as Countering Violent Extremism, began in three pilot cities last year: Minneapolis, Boston and Los Angeles. The program met some pushback from Muslim groups in those cities who said they were being unfairly targeted by the federal government.

The DHS official said the money could be used to intervene against any type of extremism, but he expected the majority of the grant applications to be aimed at combating Muslim extremism.

After the Boston Marathon bombing in April 2013, the official said, the department began rethinking its approach to fighting extremism that relied mainly on strengthening local law enforcement.

(Reporting by Julia Edwards Editing by W Simon)