Rallies and marches took place Thursday in more than a dozen states, including California, Texas, New York and Michigan, to draw attention to what organizers described in a statement as the Trump administration's "cruel and inhumane treatment of immigrants and asylum seekers."
About 60 cities and towns across the US were expected to participate, said Anna Tarkov, communications director for Families Belong Together, a group opposed to the family separations, Presstv Reported.
The group also hosted a virtual event where supporters could sign petitions, get in contact with elected officials and donate to organizations that work to protect children separated from their families.
Several hundred protesters in Los Angeles, California, gathered to voice outrage at what they see as the latest affront to American values by the Trump administration, drawing on an American history of cruelty, from the conquest of the Indians to the slave trade to the internment of Japanese-Americans during World War II.
“Taking kids from their parents is crossing a line,” said Gale Chernich, who joined the protest in Los Angeles, where many of the organizers were immigrants themselves, some of them undocumented.
Dozens of activists also took part in a rally in Rutherford, New Jersey, where the Reverend Ron Verblaauw, pastor of Rutherford Congregational Church, told NBC New York: "Separating children from families is the first sign we are not the land of the free and the home of the brave anymore. We are the scared."
The National Domestic Workers Alliance, an advocacy group, was one of several dozen organizations co-sponsoring the rallies.
"The outrage and opposition will only keep growing if the administration continues this cruelty of separating families," Jess Morales Rocketto, political director of the alliance, said in a statement.
It's the second wave of major protests against family separations across the US. Activists rallied on June 1 and filed a complaint with the Inter-American Commission on Human Rights, an agency of the Organization of American States, alleging that the US policy violates human rights.
The number of family separations has risen sharply in recent weeks, largely because of new policies by the Trump administration.
Trump has made his hard-line stance on immigration an integral part of his presidency and has promised to build a wall along the US-Mexican border to curb the flow of migrants from Mexico and Central America.
US Attorney General Jeff Sessions announced in May a "zero tolerance" policy in which all those apprehended entering the United States illegally would be criminally charged, which generally leads to children being separated from their parents.