Rwanda's education minister is under strong pressure from MPs, over what they call "genocide ideology" present in some schools in the country.
More than 800,000 people died in the 1994 genocide
A parliamentary investigation found cases where students were made to wear different uniforms according to their ethnic group and books inciting hatred.
Minister Jeanne d'Arc Mujawamariya, who MPs could sack, says those behind such incidents have been punished.
Some 800,000 Tutsis and moderate Hutus died in 100 days in the 1994 genocide.
Minister of State for Primary and Secondary Education Joseph Murekeraho has also been questioned by law makers.
Poems of hatred
Ms Mujawamariya says that the teachers responsible have been taken to court and those found guilty of inciting ethnic hatred sacked.
But the MPs say she has still not adequately answered their questions and have summoned her to appear before a commission for a third time.
Last month's parliamentary report said old books "distorting history" had been found in libraries.
Some claimed, for instance, that Tutsis should not be considered Rwandan.
The Hutu extremists behind the genocide said the Tutsis had come to Rwanda from Ethiopia.
Poems promoting hatred and division were also found in school libraries.
After the report was presented to parliament, a special commission was set up to deal with the matter as it was felt the education ministry had not done enough to resolve the problems - five years after they first surfaced.
The BBC's Geoffrey Mutagoma in the capital, Kigali, says the issue has shown the problems prevailing in Rwandan society 13 years after the genocide.
Many believe that if ethnic division is visible in schools, then the situation might be even worse at home, he says.
The present Tutsi-dominated government seized power in 1994, ending the genocide.