By Julia Edwards

WASHINGTON (Reuters) - A new White House plan aims to convene teachers and mental health professionals to intervene and help prevent Americans from turning to violent ideologies, work that is currently mostly done by law enforcement, a draft of the policy seen by Reuters shows.

The 18-page plan, to be announced on Wednesday, marks the first time in five years that the Obama administration has updated its policy for preventing the spread of violent groups. Authorities blamed radical and violent ideologies as the motives for attacks in the last year in Charleston, South Carolina; San Bernardino, California; Orlando, Florida; New York and New Jersey.

A self-styled white supremacist is accused of shooting dead nine black people inside a historic African-American church in Charleston and the other shootings and bombs were inspired by Islamist militants.

Both Republicans and Democrats in Congress have questioned Department of Homeland Security officials over the delay in updating the department's approach to countering recruitment strategies by Islamic State, which controls parts of Iraq and Syria, and other groups.

Congress does not have the authority to reject the plan, but it could withhold funding to prevent it from being fully implemented. The White House says the plan can be implemented at current funding levels, but it will need dedicated funding in the future to "fully realize the goals of the strategy."

Civil liberties groups, including the Council on American-Islamic Relations, have criticized the current model as one that sows distrust in Muslim communities in the United States. Federal prosecutors, who are charged with conducting terrorism investigations, also lead prevention efforts.

Prosecutors would still have a role in prevention efforts under the new policy, including arranging after-school programs, but they would not be allowed to use those settings for intelligence gathering.

In Minneapolis, U.S. Attorney Andrew Luger prosecuted 10 Somali-American men earlier this year for plotting to fight with the Islamic State overseas while simultaneously leading community outreach efforts with the same Somali community.

Studies have shown family members and friends are most likely to notice a loved one may be considering violence, the policy explains. But some may be reluctant to report the behavior to law enforcement.

"Successful efforts to counter violent extremism are, in large part, predicated on trust," the policy states.

Under the new guidelines, "local intervention teams" made up of mental health professionals, faith-based groups, educators and community leaders will assess the needs of individuals who may be showing signs of converting to a violent ideology.

Local law enforcement officers may also be part of the team, but not federal prosecutors.

"We determined that efforts to build intervention teams are less likely to succeed if they are driven by the federal government," said Brette Steele, acting deputy director of the U.S. government's Countering Violent Extremism Task Force, suggesting that the teams should instead be community-led.

Only when a person is believed to "pose a threat or be immediately capable of committing a crime," should law enforcement actions be taken, the policy states.

The policy also calls on the Justice Department to implement rehabilitation strategies that could include using former converts to violence as counselors for those convicted of terrorism.

(Reporting by Julia Edwards; Editing by Grant McCool and Frances Kerry)