US President Donald Trump has hosted the relatives of victims killed by illegal immigrants amid outrage over the separation of migrant families.
"Your loved ones have not died in vain," he told the group of so-called Angel Families at the White House.
Mr Trump has faced global condemnation for the US immigration policy that has seen more than 2,000 migrant children stripped from their families.
He bowed to public pressure and reversed the policy earlier this week.
The president signed an executive order on Wednesday to end the separate detention of undocumented immigrant children from their parents after illegally entering the country.
As part of the the administration's "zero-tolerance" policy, which seeks to criminally charge and jail undocumented border crossers, children cannot legally be held with their parents. They have instead been kept in separate facilities.
What did the president say?
"These are the American citizens permanently separated from their loved ones," he said on Friday, before introducing family members of victims.
"I cannot imagine it being any worse, but we promise to act with strength and resolve.
"We'll not rest until our border is secure, our citizens are safe and we end this immigration crisis once and for all," Mr Trump added.
Laura Wilkerson, whose son was killed in 2010 by an undocumented immigrant, told audience members: "None of our kids had a minute to say goodbye. We weren't lucky enough to be separated for five days or 10 days.
"We were separated permanently."
What's the context?
Approximately 2,300 children have been removed from their families since Mr Trump's "zero-tolerance" policy began in May, and housed in detention centres run by the Department of Health and Human Services.
Some shelters, including three in Texas, house so-called "tender age" children, who are under five years old.
More on child migrant separation crisis
About 500 children have been reunited with their families since May, a Homeland Security official said on Thursday. But it is unclear how the remaining families affected will be reunited.
Images of children in metal cages, and audio of young migrants crying out for their parents sparked protests and drew international condemnation from world leaders and organisations.
What is Trump's strategy?
Anthony Zurcher, BBC News, Washington
After a week on his heels, Donald Trump has begun his counterattack.
On Friday morning, the president tweeted about the "phony stories of sadness and grief" coming from the US-Mexico border - a clear attempt to undermine media reports of traumatised undocumented immigrant families separated by US officials.
On Friday afternoon, the president stood alongside relatives of those killed by undocumented immigrants. These were the stories the media ignores, he said. These were families that had been "permanently separated".
He cited raw numbers of murders, rapes and robberies committed, and dismissed statistics that show foreign born in the US commit crimes at a lower rate than the general population.
"You hear that they're better people than our citizens," Mr Trump said. "It's not true."
After spending the early part of the week insisting on the need for congressional immigration action, by Friday he had abandoned those efforts - tweeting that Republicans were "wasting their time" - and is girding for mid-term warfare.
The president's political strategy appears to be to rally his base with tales of lawlessness and rampage. He's made economic arguments against immigration in the past, about stolen jobs and strained social services, but now he is focused on fear.
Republicans in the House of Representatives have scrambled this week to drum up enough support for a "compromise" immigration bill addressing the crisis. But the bill was delayed to Friday before being pushed back to next week.
Earlier on Friday, Mr Trump tweeted congressional Republicans "should stop wasting their time on Immigration until after we elect more Senators and Congressmen/women in November".