(CNN) — Anne Smedinghoff lived inside a heavily secured compound.
But the public diplomacy officer for the U.S. Embassy in Kabul was always pushing to get out.
"She particularly enjoyed the opportunity to work directly with the Afghan people," her parents said in a statement, "and was always looking for opportunities to reach out and help make a difference in the lives of those living in a country ravaged by war."
This weekend, the 25-year-old was trying to do just that -- delivering books to a school in southern Afghanistan -- when a suicide bomber smashed into her convoy Saturday. She is believed to be the first U.S. diplomat killed since the September attack in Benghazi, Libya.
Her death was a grim reminder of the risks and importance of pushing for change in "one of the toughest places on earth," U.S. Secretary of State John Kerry said Sunday.
It was an "extraordinary harsh contradiction," Kerry said, to see an attacker kill "a young 25-year-old woman with all of the future ahead of her, believing in the possibilities of diplomacy, of changing people's lives, of making a difference, having an impact, who was taking knowledge in books to deliver them to a school."
Officials did not say who they believe was behind the blast. But Kerry offered a sharp condemnation of the violence as he spoke Sunday to U.S. diplomats stationed in Istanbul.
"The folks who want to kill people, and that's all they want to do, are scared of knowledge. And they want to shut the doors and they don't want people to make their choices about the future. For them, it's 'You do things my way and if you don't, we'll throw acid in your face. We'll put a bullet in your face,' to a young girl trying to learn," Kerry said. "So this is a huge challenge for us. It is a confrontation with modernity, with possibilities, and everything that our country stands for, everything we stand for, is embodied in what Anne Smedinghoff stood for."
Smedinghoff joined the Foreign Service three years ago, soon after graduating from Johns Hopkins University.
"There was no better place for her," her parents, Tom and Mary Beth Smedinghoff, said in a statement, describing their daughter as "strong, intelligent, independent, and loving."
After a tour of duty in Caracas, Venezuela, Smedinghoff volunteered for an assignment at the U.S. Embassy in Kabul and had been working there since July, her parents said.
"We are consoled knowing that she was doing what she loved, and that she was serving her country by helping to make a positive difference in the world," they said.
Smedinghoff's Facebook profile gives a glimpse of her life in Afghanistan. One photo shows a group skiing in the Afghan mountains. Another shows her standing behind a lectern at the embassy, surrounded by American flags. Another, titled "Helicoptering around Helmand," shows a smiling Smedinghoff sitting beside men in camouflage, wearing a helmet and a flak jacket.
"She was living in a compound that was heavily fortified," Tom Smedinghoff told the Chicago Tribune, "and she was always trying to get out and do things for the population."
He said that she had been working with local schools and businesses, helping women and working on projects to promote equality for women.
On Easter, her father said, she excitedly talked about Kerry's recent visit.
"She sounded so upbeat and so positive and so excited about all the work she'd been doing," he said.
Kerry was emotional Sunday as he spoke of Smedinghoff's death. He said that they met two weeks ago when he visited Afghanistan.
"I remember her -- vivacious, smart, capable, chosen often by the ambassador there to be the lead person because of her capabilities," he said. "So it's a grim reminder to all of us, though we didn't need any reminders, of how important and also how risky carrying the future is with people who want to resist."
But despite the opposition, he said, many people believe in the changes Smedinghoff and others in the U.S. diplomatic corps are pushing to promote.
"I think every single one of us can stand very, very proud of Anne and her cohorts, as America stands very, very proud of each and every one of you. This is not easy work. It's not easy being away from home. It's not easy packing up, breaking ties to family and friends and coming over to represent your country," Kerry told the diplomats in Istanbul on Sunday. "But the whole world is in a state of transition right now. It is important for us to be able to help to bring stability and rule of law and alternatives to this kind of nihilistic violence that simply destroys and steals lives without offering any other constructive purpose whatsoever."
In Smedinghoff's memory, CNN affiliate WBBM reported, flags lined the road near her family's Illinois home on Sunday.
A large photograph she posted on her Facebook profile less than two weeks ago shows another road on the other side of the world, lined with Afghan flags.