The Democratic leader's tweet storm comes the same day Trump held a roundtable discussion with California Republican lawmakers where he praised them for holding a "rebellion" against the state's sanctuary policies.
"The state of California's attempts to nullify federal law have sparked a rebellion by patriotic citizens who want their families protected and their borders secured", Trump said.
"It's a crisis", Melendez said of the situation.
Responding to the meeting, Gov. Jerry Brown past year that bars police from asking people about their immigration status or helping federal agents with immigration enforcement. But the Trump administration has sued to reverse it, calling the policies unconstitutional and unsafe. County governments, including Orange County and San Diego County, California's second largest county, have also joined in opposition.
Sanctuary policies undermine lawful immigration enforcement efforts and are responsible for the release of criminal aliens into American communities. While multiple localities in the state have said they will opt out of the sanctuary policy, the laws are broadly popular in the state, with support from more than 50% of residents, according to polling.
"California's law provides safe harbor to some of the most vicious and violent offenders on Earth, like MS-13 gang members, putting innocent men, women, and children at the mercy of these sadistic criminals", Trump said.
"These aren't people", Trump emphasized dramatically, "these are animals".
Supporters of the law believe it makes immigrants who are living in the country illegally more likely to report crime and cooperate in law-enforcement investigations.More news: Republican governors back Trump's nomination for Nobel peace prize
The vote is mostly symbolic, the city will still abide by all immigration laws at both the state and federal level. He said the leaders were "working with the administration". "I think the entire Trump views on immigration is heartless", the former presidential candidate said.
Attorney General Jeff Sessions was also in attendance.
Numerous legislators demanding action face potentially competitive re-election races in congressional districts with large numbers of Hispanic, suburban or agriculture-industry voters with pro-immigration views.
He noted that the wall is already under construction in California on the border with Mexico.
Senate Democrats, however, have objected to simply handing Trump all the monies needed to complete the project.
"Those are the bad laws the Democrats gave us". The bases would house minors under the age of 18 who either cross the border alone or had their parents separated from them by government officials.
Trump also told Nielsen that she was "doing a good job", one week after berating her during a cabinet meeting for failing to halt border crossings.
Trump will meet at the White House with the sixteen elected officials, including Fresno County Sheriff Margret Mims, Stanislaus Couny Sheriff Adam Christianson and House Majority Leader Kevin McCarthy.