Salvadorean President Tony Saca has criticised a decision to re-open an inquiry into one of the bloodiest incidents of the country's civil war.
The Inter-American Commission on Human Rights agreed last week to re-examine claims government troops killed more than 500 peasants in El Mozote in 1981.
Mr Saca said re-opening such cases could be dangerous for El Salvador because it had put its past behind it.
The army has denied any involvement in the massacre in the mountain village.
'Peace and stability'
Mr Saca told a news conference: "Re-opening cases is returning to a past that definitely could be very dangerous for the country."
The president also rejected calls to revoke El Salvador's amnesty law, saying it had brought "peace and stability".
The commission, a branch of the Organisation of American States, voted last week to re-open the file on El Mozote.
Officials said human rights groups wanted the case re-examined because they believed new forensic evidence suggested the authorities had approved the killings.
The Roman Catholic Church in El Salvador has also pushed for a new investigation, alleging government responsibility.
A Church spokesman said members of the US-trained Atlacatl Battalion "killed hundreds of civilian residents, including women, children and the elderly", over the course of three days in December 1981.
A truth commission set up by the UN in the 1990s concluded that at least 500 villagers were killed. Other investigators put the figure much higher.
More than 75,000 people died during El Salvador's 12-year civil war between the US-backed government and left-wing rebels - which ended in 1992.
A general amnesty was declared in 1993 by then President Alfredo Cristiani.