The US president refuses to back down on the 18th day of a partial shutdown, using examples of Americans murdered by immigrants.
Donald Trump has claimed the US-Mexico border issue is a humanitarian crisis of “the heart and soul” in a plea to get funding for his wall.
The US president, addressing the nation on TV from the Oval Office for the first time, said Congress needed to approve the $5.7bn (£4.5bn) wall on the southern border on security and humanitarian grounds.
On the 18th day of a partial government shutdown over the wall funding, Mr Trump called on newly empowered Democrats to meet with him, saying it was “immoral” for “politicians to do nothing”.
He said he was conceding to the Democrats in making the wall steel rather than concrete, as he painted illegal immigrants as criminals and drug dealers who put a strain on public resources and fuel the deaths of Americans by drugs.
“More Americans will die from drugs this year than were killed in the entire Vietnam War,” he said.
The president said children illegally brought into the US are “used as human pawns by vicious coyotes and ruthless gangs”, while women and children are “the biggest victims by far of our broken system”.
“This is the tragic reality of illegal immigration on our southern border,” he added.
“This is the cycle of human suffering that I am determined to end.”
He said his administration has given Congress a “tremendous” proposal to secure the border, developed by law enforcement professionals and border agents.
America would be “safer than ever before” under the proposal, which includes “cutting-edge technology for detecting drugs, weapons, illegal contraband and many other things,” he said.
He insisted his plan would mean illegal immigrant children can be “safely and humanely returned back home”.
The Democrats have “refused to provide our brave border agents with the tools they desperately need to protect our families and our nation,” he added.
Mr Trump said the wall is not “immoral” as he claimed wealthy politicians build walls and fences around their homes because they love the people on the inside, not because they hate people on the outside.
The president used a series of murders to highlight why “illegal aliens” need to be kept out, from a police officer killed on Boxing Day to a veteran who was raped and murdered in California.
He claimed to have met “dozens of families whose loved ones were stolen by illegal immigration…I’ve held the hands of the weeping mothers”.
“How much more American blood must we shed before Congress does its job?” he added.
Mr Trump asked those who “refuse to compromise” to “imagine if it was your child, your husband or your wife whose life was so cruelly shattered and totally broken”.
He appealed to Congress to end “this crisis” and for every American to “call Congress” and tell them to “secure our border.
“This is a choice between right and wrong, justice and injustice,” he finished.
House speaker Nancy Pelosi and Senate Democratic leader Chuck Schumer spoke after the president to address their concerns.
Mrs Pelosi accused Mr Trump of being “full of misinformation and even malice”, and choosing fear over facts.
She said the Democrats also want a secure border, but Mr Trump’s wall is not the solution, as she offered options including building infrastructure and installing new technology.
“The fact is: President Trump must stop holding the American people hostage, must stop manufacturing a crisis, and must re-open the government,” she said.
Mr Schumer was harsher in his criticism, accusing Mr Trump of throwing a temper tantrum and using millions of Americans as leverage.
He said Mr Trump needs to re-open government while allowing the debate over border security to continue.
“Most presidents have used Oval Office addresses for noble purposes,” Mr Schumer said.
“This president just used the backdrop of the Oval Office to manufacture a crisis, stoke fear, and divert attention from the turmoil in his administration.
“The symbol of America should be the Statue of Liberty, not a thirty-foot wall.”