He was responding during a White House event to a point made by a California sheriff about the MS-13 gang, which was started in the 1980s by immigrants from Central America.

President Trump used extraordinarily harsh rhetoric to renew his call for stronger immigration laws Wednesday, calling undocumented immigrants "animals" and venting frustration at Mexican officials who he said "do nothing" to help the United States.

“We have people coming into the country or trying to come in, we're stopping a lot of them, but we're taking people out of the country. You wouldn't believe how bad these people are," Trump said. 

"These aren't people. These are animals."

Trump's comments came in a freewheeling, hour-long White House meeting with local California leaders opposed to so-called "sanctuary city" policies. "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," he said.

His comment about "animals" came after Fresno County Sheriff Margaret Mims complained that state law forbids her from telling U.S. Immigration and Customs Enforcement about undocumented immigrants in her jail — even if she suspects they're part of a gang.

"There could be an MS-13 member I know about. If they don’t reach a certain threshold, I cannot tell ICE about it," she said.

Trump's remarks were reminiscent of his first press conference as a presidential candidate in 2015, when he said the United States had become a "dumping ground" for people other countries didn't want.

"When Mexico sends its people, they're not sending their best," he said then. "They're bringing drugs. They're bringing crime. They're rapists. And some, I assume, are good people."

Trump has been particularly vocal in opposing so-called "sanctuary city" policies, in which some jurisdictions have refused to fully cooperate with federal immigration authorities. On Wednesday, he highlighted California cities who do cooperate, inviting mayors and sheriffs opposed to the state's predominant policy.

"Each of you has bravely resisted California's deadly and unconstitutional sanctuary state law," Trump told them.