The Decatur School District has expelled the students for a year from schools in the city, for fighting at a football game.

The Rev Jackson has been heading protests against the decision, and on Sunday he led a crowd of about 2,000 people in a march through the Decatur's streets.

He told the protestors he would visit the schools on Tuesday to demonstrate and force the authorities to arrest him, saying he was prepared to go to jail over the issue.

"On Tuesday morning, we're going to cross the line. If Dr King could do it in Birmingham ... and Mandela could do it in South Africa, we can do it in Decatur," he said.

The fight happened in September, at a game between Decatur's Eisenhower and MacArthur high schools.

The Reverend Jesse Jackson: "We're going to cross the line"

Pupils from the two schools, as well as from the city's third high school, Stephen Decatur, were involved.

The original ruling made by the school board was to expel the six students for two years. This was cut on appeal to expulsion for one year.

Another pupil withdrew from school before he could be expelled.

Rev Jackson had originally demanded the pupils be reinstated at their schools, but then said alternative education would be acceptable as part of a scheme to get them back into the school system.

Last week, four students, including two who were expelled, were charged with "mob action", and another was charged with "aggravated battery and resisting a police officer".

'Unfortunate'

Rev Jackson said he was backing down, because he did not want to risk further criminal charges against the students. Now it appears he has altered his stance again.

He wants the expulsions to be cut further, so that if the students are doing well, they can return to school in January.

He has said the issue is not a question of racism, but of whether the students were treated fairly.

Jackie Goetter, president of the school board, said on Sunday that she knew nothing about Rev Jackson's threat of further demonstrations.