The United States officials said on Thursday that the US government will declassify documents from US military and intelligence agencies related to Argentina’s, so called "Dirty War."
The "Dirty War" is the name given to a period of violence between 1976-1983 when Argentina's military government cracked down on left-wing opposition.
The unsealing of the files coincides with President Barack Obama’s visit to Argentina next week on the 40th anniversary of the country's 1976 military coup.
The US initially supported the coup, which led to a military dictatorship. Argentina returned to democracy in 1983.
President Obama’s National Security Advisor Susan Rice said that the declassification follows a request from Argentina.
"On this anniversary and beyond, we’re determined to do our part as Argentina continues to heal and move forward as one nation," Rice said during a speech at the Atlantic Council in Washington.
An administration official said the declassification effort will include records from US law enforcement agencies, the Department of Defense, the Department of State, and the presidential libraries at the National Archives.
"The president is committed to continuing to support Argentine efforts to address the human rights violations committed during the "Dirty War" and will highlight this commitment during his visit to Argentina next week," the official said.
An analyst at the National Security Archive, Peter Kornbluh, said that the US president should be applauded for engaging in "declassified diplomacy."
Kornbluh said that Obama’s decision "not only provides a historical atonement for early U.S. support for the coup and the repression in its aftermath, but also can provide actual evidence and answers to the families of human rights victims who continue to search for their missing loved ones in Argentina, 40 years after the coup took place."
Following pressure from human rights groups, in 2002 the US unsealed partly 4,700 State Department files on Argentina from the period.
The files showed that some top American officials had been aware of the Argentine government’s brutal methods.
The files include conversations between US Secretary of State Henry Kissinger and Argentina's Foreign Minister Cesar Augusto Guzzetti, in which Kissinger appears to condone the military’s crackdown.
"If there are things that have to be done, you should do them quickly," Kissinger told Guzzetti.
Obama plans to visit Buenos Aires before embarking on a significant visit to Havana where differences with the Cuban government over human rights remain an irritant even as the United States seeks to begin a new chapter of engagement.