Scientists from around the world are calling on Mexican leaders to resolve a dispute that is tearing apart a leading Latin American research institute.

Two nanotechnology researchers at the Institute for Scientific and Technological Research of San Luis Potosí (IPICYT) claim they are being persecuted by the organization's administrators, after they testified in a long-running probe into the former director, José Luis Morán-López, who was ousted for nepotism in April. Morán-López denies impropriety and is appealing.

Both researchers, brothers Humberto and Mauricio Terrones Maldonado, have since lost their administrative posts. Humberto was head of the advanced-materials department, and Mauricio headed the graduate research programme. Their students claim that the current administrators are now transferring lab facilities funded by the Terrones' grants to others.

The Terrones appealed to prominent scientists, including Nobel-prizewinning chemist Harold Kroto, one of the discoverers of 'buckyball' molecules. Last week, Kroto and 30 other scientists signed a letter in support of the pair, addressed to Mexican President Felipe Calderón Hinojosa and Mexico's national council of science and technology funding (CONACYT).

Kroto says that he fears the attacks on the Terrones will destroy one of Latin America's most promising physical-science centres and drive the two researchers abroad. "The Terrones could easily have won research positions anywhere, but they chose to go back to Mexico to help young scientists," says Kroto, who is based at Florida State University in Tallahassee. "They have made a massive contribution to science. They now have had a kick in the teeth."

"The solidarity of the international community has been overwhelming," says Humberto. "What we want is Mexican leaders to solve the problem. Our system doesn't seem to allow for success of young scientists."

The institute's current department heads responded to the scientists' letter on 28 June. In a letter to Kroto, they decry his involvement in the affair, writing that his actions are "unbalanced, based on false premises and damage the prestige of our institute". Current IPICYT director David Rios Jara told Nature that the Terrones are very ambitious and "the only way they will be quiet is when they have their own centre. They don't like authority."