An immigrant-rights advocate was injured with a chemical spray Sunday when the group he was with confronted an anti-illegal-immigrant group outside a California church.

Police were investigating allegations that an opposing protester was responsible, police Capt. John McGinty said.

A woman and her U.S.-born infant son are living at the United Church of Christ in Simi Valley as part of what is known as the New Sanctuary Movement.

The group arranges church accommodations for illegal immigrants in the U.S.

Members of the anti-illegal immigration group Save Our State organized the rally, which drew about 120 protesters and counter-protesters. It said members hoped to make a citizen's arrest of the woman, who has identified herself only as Liliana.

Save Our State is a two-year-old nonprofit organization that describes illegal immigration as "disastrous" and promotes "aggressive activism and advocacy."

A statement on the group's Web site says that California is filled with people "who are weak and unwilling to wage battle against the Mexican racialists and the vast open borders lobby."

The faith-based New Sanctuary Movement's Web site says it "will enable congregations to publicly provide hospitality and protection to a limited number of immigrant families whose legal cases clearly reveal the contradictions and moral injustice of our current immigration system while working to support legislation that would change their situation."