Chanting "Trump has to go," "No Trump, No KKK, No Fascism in USA" and other slogans, the crowd called on people to defy Fridays executive order that slaps a 90-day ban on travel to the country by citizens of seven Muslim-majority countries and a 120-day suspension of the U.S. refugee program.
At least seven foreign nationals have been detained at LAX and told they were no longer welcome, the Los Angeles Times reported, noting that they were allowed to board flights before the order took effect.
The protesters demand was echoed by Los Angeles Mayor Eric Garcetti, who tweeted Saturday night that "Los Angels will always be a place of refuge."
A candlelight vigil and protest were scheduled to be held Sunday.
Trumps travel ban, widely described as a "Muslim ban," has triggered confusion and chaos across the country and drawn concern and criticism from across the world.
Similar protests have erupted at airports in many other cities. In Chicago, more than 1,000 rallied at the OHare airport. In Denver, Colorado, dozens of protesters gathered outside the international airport to show support for refugees.
This was the second weekend of demonstrations in Los Angeles after Trump was sworn into the Oval Office. More than 1 million people came out last weekend for the Womens March.