John Kerry said he will deliver the first batch of declassified documents related to America’s role in Argentina’s 1976-83 military dictatorship, a seven-year period in which thousands of leftwing activists were murdered.

The delivery comes during a period of warming relations between the two countries, as center-right president Mauricio Macri, who was elected in December, has rejected the protectionism of his predecessors and sought a diplomatic rapprochement with the US.

“I want to note that the relationship between the United States and Argentina is an exciting, forward-looking one. But we’re also conscious of the lessons from the past,” Kerry told reporters during a visit to Buenos Aires.

“Last March, in response to a request from President Macri and human rights groups, President Obama promised to identify and share additional US government records, many from intelligence and law enforcement agencies. So later today, I will deliver the first tranche of those declassified documents to President Macri, with more to come in the future.“

The recent effort follows the declassification in 2002 of more than 4,000 state department cables and other documents related to Argentina’s seven-year dictatorship, which the US government initially supported.

During a visit to Argentina in March, Barack Obama said the United States was slow to condemn human rights atrocities there. He also dropped white roses commemorating the dead into the La Plata River, beside the Monument to Victims of State Terrorism, which is inscribed with 20,000 names.

While many Argentines appreciated the gesture, some survivor groups condemned Obama’s visit as a provocation, especially as it coincided with the 40th anniversary of the coup.

Between 1976 and 1983, the Argentine military killed an estimated 30,000 dissidents, many of them tied to labor unions or leftist groups. Survivors of the crackdown say one of the military rulers’ tactics was so-called “death flights”, in which political opponents were tossed into aircraft, stripped and then thrown alive into the river or the Atlantic Ocean to drown.

