"This is something that our partners to the south need to work with us on, so that we do not have to feel the brunt of this pressure", Judd said.
Tijuana Mayor Juan Manuel Gastelum said the throngs of migrants who have descended on his city is tantamount to a humanitarian crisis, and he declared an emergency. "That's in addition to 5,000 already here".
"But we also understand that our constituents have stated quite clearly that they want to see our border protected", she added. Democrats and even some lawmakers in Trump's own party have resisted his calls to fund his proposed border wall. He went on to suggest that it would be "very SMART" if Mexico stopped the caravans before they arrived at the border, "or if originating countries would not let them form (it is a way they get certain people out of their country and dump in U.S. No longer)".
The U.S. Department of Homeland Security said U.S. Customs and Border Protection officers were struck by projectiles thrown by the migrants.
Appearing to defend her agency's response to the hundreds of migrants who approached the U.S. -Mexico border on Sunday, Nielsen said she would not "tolerate" any kind of "lawlessness" from anyone hoping to seek asylum in the U.S.
He wrote on Twitter, "Mexico should move the flag waving Migrants, many of whom are stone cold criminals, back to their countries". He has insisted that each person seeking asylum wait on Mexico's side of the border until their application is processed and their case decided.
One of the migrants at a temporary shelter in Tijuana, Mexico.
"Tear gassing families seems unnecessary", Lee Gelernt, the deputy director of the ACLU Immigrants' Rights Project, told CNN.
"Most of them are adult males".
Other footage shows Border Patrol agents firing tear gas canisters at migrants who were trying to storm the border.
Trump wants migrants to remain in Mexico while their USA asylum cases are adjudicated.