WASHINGTON — President Donald Trump used a White House event Monday to pay tribute to federal immigration officials, returning to the fight over the U.S. southern border.

The president was honoring employees of the U.S. Immigration and Customs Enforcement and the Customs and Border Protection. The federal agencies have been thrust into the debate over the Trump administration's separation of migrant children from their parents after they illegally crossed the U.S.-Mexico border.

"We love you, we support you, we will always have your back," Trump said. He added: "For America to be a strong nation, we must have strong borders."

Trump has assailed some Democratic lawmakers for seeking to abolish ICE ahead of the November midterm elections. In a letter to state and local leaders, Trump wrote that ICE workers had been subjected to a "nationwide campaign of smears, insults and attacks" by politicians "catering to the extreme elements in our society."

At the White House event, Trump said that most people support ICE and that opponents are "just a small group that gets a lot of publicity."

"They have no courage, they have no guts, they just have big loud mouths," Trump said.

Trump has made border security a key part of his message as he tries to maintain Republican control of Congress in the November elections.

Before the president arrived, the White House held a panel discussion on immigration with several state and local officials, who pointed to the role that a secure border plays in the fight against terrorism and drug trafficking and questioned calls to abolish ICE.

Republican Sen. David Perdue of Georgia, who has worked closely with the administration on immigration legislation, said he struggled to see the point of eliminating the federal agency, likening it to someone saying, "I want to get rid of the Marines."

"I just think it's unconscionable, and frankly, I think it's downright unpatriotic and treasonous," Perdue said.