Activities of the Ku Klux Klan and an increase in anti-Semitic vandalism in the Washington area have strengthened the resolve of the religious community to battle bigotry.

Tonight at 6, Christian and Jewish leaders will join with District of Columbia and Montgomery Country officials in a Service of Prayer and Justice on the steps of the National City Christian Church, 1401 Massachusetts Ave. NW.

The service is sponsored by the Ad Hoc Coalition for Community Unity, a group of 34 religious, civil rights, community, labor and business organizations that was created last month in response to Ku Klux Klan plans for demonstrations in this area. The Klan has scheduled a rally this afternoon near Rockville.

Tomorrow afternoon, Christian neighbors of Shaare Tefila Congregation in Silver Spring and religious leaders from the surrounding area will join young people of the synagogue in an attempt to clean walls desecrated this week by anti-Semitic graffiti. Montgomery County police are investigating that incident but said yesterday that they have no suspects.

Responding this week to the desecration and the Klan activities, Roman Catholic Archbishop James A. Hickey and his two auxiliary bishops joined in issuing a statement condemning anti-Semitism and racism as sinful and calling membership in the Ku Klux Klan "incompatible with the teaching of the Catholic Church."

Episcopal Bishop John T. Walker likewise condemned the "increased activities of the Ku Klux Klan and the hate-mongering they engender." Like his Roman Catholic counterparts, Walker said it is "appalling" that people who "call themselves Christian" are part of the Klan.

Marshall Levin, executive director of Shaare Tefila congregation, said the Conservative synagogue has "been flooded with calls" from persons asking "what can we do to help?" following disclosure that vandals had spray-painted anti-Semitic slogans and symbols on the synagogue's wall Monday night.

Shaare Tefila is a member of an interreligious group in the Colesville area called the Colesville Council of Community Congregations. The Rev. Ernest Bordner of the Colesville United Methodist Church, convener of the council, said that as soon as he learned about the desecration, he "sent a letter to every participating congregation" advising them of the incident.

He predicted that many of the clergy in the council would "deal with" the anti-Semitic problem from the pulpit tomorrow. Levin said representatives of the 18 congregations in the council would be on hand for the clean-up tomorrow.

Participants at tonight's service will include D.C. Del. Walter Fauntroy; Montgomery County Executive Charles Gilchrist; D.C. School Superintendent Floretta McKenzie; Archbishop Hickey; the Rev. John O'Conner of the Roman Catholic archdiocese; Rabbi Andrew Baker, director of the Washington office of the American Jewish Committee, and the Rev. Edward Hailes, president of the D.C. chapter of the NAACP.