LOS ANGELES — President Donald Trump returned Friday to one of the most hostile political territories for him in the U.S.— California.

After a stop at the U.S. border with Mexico in Calexico, California, Trump arrived in Los Angeles to attend a fundraiser in a state where his job-approval ratings have been dismal and his past visits have been met by protesters. This time around, a few protesters held up a sign saying "Trump-Pence must go" as the president's motorcade drove nearby on Sunset Boulevard on the way to a Beverly Hills mansion.

Trump was also expected to make an unannounced side trip to the coastal city of Rancho Palos Verdes for a dinner at his Trump golf course overlooking the Pacific Ocean with a group that included members of the City Council, the Los Angeles Times reported.

Trump hasn't been shy at hurling jabs-- during his visits or year-round, really, from his Twitter account-- at California's Democratic leaders and their policies. This time was no exception. During his border visit, he complained that California's political leaders are whiners.

"I’m talking about the politicians in California. They complain,” Trump was quoted as saying by CNN in Calexico, California, pointing to the state's recent wildfires that claimed thousands of homes as an example.

He went on to say, "When their forests go up (in flames), they complain. They gotta take care of their forests a lot better. "

His visit came as the president was once again redefining his immigration policies, which have been widely criticized as unnecessarily cruel by many California leaders with close economic or cultural ties to nearby Mexico. Trump backed off Thursday from his latest threat to close the U.S.-Mexico border in the face of an immigration surge.

He flew to Los Angeles from a visit to the U.S. side of the border with Mexico. There, he took a look at a two-mile refurbished section of fencing and took aim at the surge in migrants, saying there's no room left in the U.S. for them. He was briefed on border security, which is sure to become a core part of his 2020 bid for re-election.

He called the increase in immigrants showing up at the border “a colossal surge, and it’s overwhelming our immigration system."

He added, "We can’t take you anymore. Our country is full.”

The president arrived in Southern California still basking in his attorney general's recent synopsis of special counsel Robert Mueller's report that found no collusion between his campaign and Russia in the 2016 election. “According to polling, few people seem to care about the Russian Collusion Hoax, but some Democrats are fighting hard to keep the Witch Hunt alive,” Trump tweeted ahead of his border visit.

Trump's visit could be a much-needed boost to the spirits of Los Angeles-area Republicans, said Shawn Steel, the Republican National Committeeman from California, who called Trump's visit an "energizer." The GOP saw major losses in the 2018 midterm elections in California.

The "giant dark cloud" of the Mueller report has lifted, Americans are enjoying another year of a strong economy and Trump has scored foreign policy successes, Steel said. At the same time, he said Democrats in power were making missteps unpopular with moderates. He cited Gov. Gavin Newsom's plan to end the death penalty as an example.

Steel said among the party's goals is winning back the four congressional seats it lost in November in the traditional GOP stronghold of Orange County, just south of Los Angeles.

But it won't be easy. Polls show Trump remains deeply unpopular in California. A Quinnipiac University poll released in February showed only a 28% job-approval rating across the state for Trump. Having won seven seats in the midterm election, Democrats hold a 46 to seven advantage in congressional seats from California.

As of February, Democrats held an almost two-to-one voter registration advantage over Republicans. Since 2011, the Republican percentage of the vote has slipped from 30.9% to 23.6%, according to the California Secretary of State's office.

"They are becoming an endangered species," said Susan Estrich, a political science professor at the University of Southern California.

She said there is no getting around Trump's unpopularity.

"There's probably no state in the country that likes Trump least," Estrich said.

Contributing: Associated Press