US Secretary of State John Kerry visits Brazil Tuesday following a stop in Colombia that saw him defending American surveillance programs.
Since the vast telephone and Internet surveillance programs were brought to light by intelligence leaker Edward Snowden, Washington officials have insisted they are perfectly legal and have played a role in foiling dozens of terrorist attacks.
"I think it's very obvious to everybody that this is a dangerous world we're living in," Kerry told reporters in Bogota Monday, referring to the September 11, 2001 terrorist attacks.
"And we are necessarily engaged in a very complex effort to prevent terrorists from taking innocent lives in many different places."
He described his conversation on the matter with Colombian counterpart Maria Angela Holguin as "very, very straightforward."
"Frankly, we work on a huge number of issues and this was, in fact, a very small part of the overall conversation," he said.
He added that it was a topic "in which I am confident that I was able to explain thoroughly, precisely, how this has received the support of all three branches of our government, it has been completely conducted under our Constitution and the law, and how we have respected the concerns of other countries and will continue to."
In Colombia, the secret US Internet surveillance allowed Washington to map FARC rebel movements from 2008 until earlier this year, Brazil's O Globo newspaper reported last month.
Elsewhere in Latin America, US intelligence scooped up data on oil and military spending in Venezuela and on energy and drug trafficking in Mexico, according to the daily.
After the O Globo report, Colombia complained that the surveillance violated its people's right to privacy, as well as international telecoms accords, and said it would seek an explanation from the United States.
Brazil's foreign minister, meanwhile, said last week that allegations Washington snooped on Brazilians, also reported by O Globo, "cannot be left out of the bilateral US-Brazil agenda."
Kerry also met with officials overseeing peace talks with the leftist Revolutionary Armed Forces of Colombia (FARC), Latin America's oldest insurgency, which have been held in Cuba since November.
"As a friend of Colombia, President (Barack) Obama wants the people of this country to know that when you achieve that peace, the United States of America will do everything in our power to help respect it and to help you to be able to implement it," Kerry said.
Colombia is the closest US ally in South America, and has received more than $8 billion since 2000 for fighting drug traffickers and rebels.
Kerry also donned casual clothes and played volleyball with soldiers and police who lost limbs to land mines and who played the game in wheelchairs.