About 250 students boycotted classes at Loudoun County High School yesterday protesting the school's refusal to replace a wooden Confederate flag emblem chopped down by a black Leesburg resident.

About 30 state troopers and Leesburg police were called to the school twice yesterday by school officials who feared an outbreak of racial violence, Leesburg, Police Chief James Kidwell said last night.

About one-fourth of the school's 1,000-member student body disobeyed the instructions of school principal Kenneth Cubert to return to class yesterday morning, and instead engaged the principal in a "healthy discussion" of the controversial issue, Culbert said last night.

Police did not intervene, although one Leesburg police officer, Douglas Hickman, said last night he watched while "a few fights" broke out among students leaving school.

The question of replacing the painted flag that had been carried by a Confederate cavalryman atop a 4-by-6-foot wooden sign at the school, has been an issue since the father of a black student destroyed it last year, Culbert said.

Gene Ashton, a Leesburg musician, said last night he had chopped off the flag with an ax because it symbolized black oppression.

"There are strong feelings about this issue" among students about one-fifth of whom are black, Culbert said.

"One group of students feels the flag is offensive and should be changed, another likes it the way it is, another feels it should be changed from a flag to a sword, another group thinks it should be changed from a Confederate flag to a school flag," the principal said. "It's a complicated issue."