Chilean President Sebastian Pinera has said he will formally ask the US for classified intelligence documents on human rights violations during the rule of Gen Augusto Pinochet.
Mr Pinera was speaking a day after US President Barack Obama said he would consider any Chilean requests.
Mr Obama - who was visiting Chile - ducked a request that he apologise for US support for Gen Pinochet.
More than 3,000 Chileans were killed under military rule in 1973-90.
More than 1,000 human rights cases are still unresolved, and hundreds are being investigated by Chile's independent judiciary.
In an interview with the Associated Press, Mr Pinera said his government was "categorically committed to contribute to the search for truth so that justice is done in all of these human rights cases".
"If there is information that a friendly government such as the US can provide to us, that advances the speed and strength of Chilean justice, of course we're going to ask for it," he added.
On Monday Chile's centre-left opposition coalition urged President Obama to apologise for the US role in the coup that brought Gen Pinochet to power.
It also asked him to share uncensored versions of thousands of CIA documents that might shed light on human rights abuses.
Answering questions from journalists, Mr Obama did not respond to the request for an apology, but said he would consider any formal request for information.
He acknowledged that US relations with Latin America had at times been "extremely rocky," but said he could not "speak for all the policies of the past".
"It is important for us to learn from our history, to understand our history, but not be trapped by it," Mr Obama added.
Human rights groups and the Chilean opposition allege the CIA was closely involved in the military coup that overthrew left-wing President Salvador Allende in 1973.
Mr Allende's death as troops attacked the presidential palace - long regarded as suicide - is among the cases currently being investigated.
Mr Pinera is Chile's first conservative president since the end of military rule in 1990.