Sign-carrying blacks and white-robed Ku Klux Klansmen marched through the same streets and rallied at the same square in this racially tense northern Mississippi city yesterday. There were three arrests during scattered incidents of violence at the Klan rally and at the police station.

About 600 members and supporters of the United League of North Mississippi ended their rally at the courthouse moments before about 50 Klansmen, carrying wooden nightsticks, and 100 sympathizers began their procession. Both rallies were conducted under heavy police security.

Klan speakers called for a "white power" drive and urged whites to protest a four-month economic boycott which blacks have staged against merchants in protest of alleged police brutality and job discrimination.

When a young white man yelled, "The Klan stands for hatred . . . you call yourselves Christians," Klansmen broke ranks and rushed the man. But police in riot fear removed and arrested the man. Later identified as David Ohmes, of Okolona, he was charged with inciting to riot, and released on bond.

Joseph Shapiro, Tupelo correspondent for the Memphis (Tenn.) Commercial Appeal, was arrested as he attempted to take photographs. He was later released on $1,000 bond after being charged with inciting to riot.

Later, at the police station, a scuffle broke out between Freed Crawford, a black and one of five Justice Department officials monitoring the marchers, and H.E. Cruber of Tupelo, who had remarked ". . . goddamn niggers in here." Cruber, who was brandishing a heavy chain, was charged with assault.