LOS ANGELES – Taking direct aim at California, a new report from President Donald Trump's administration says homelessness could be dramatically reduced by slashing restrictions on housing construction and being less tolerant of people sleeping on the streets.

The Council of Economic Advisers' report was released as Trump takes a two-day swing through California for speeches and fundraising, while taking aim at liberal policies on homelessness.

“We can’t let Los Angeles, San Francisco and numerous other cities destroy themselves by allowing what’s happening,” Trump told reporters Tuesday aboard Air Force One. He avoided offering specific solutions.

“The people of San Francisco are fed up and the people of Los Angeles are fed up, and we’re looking at it, and we will be doing something about it at the appropriate time,” Trump said.

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The report, issued days after a delegation of Trump officials visited Los Angeles to discuss homelessness, presents a conservative approach to focusing on the problem. More liberal prescriptions favored in the city include a massive and costly plan to build apartments for the homeless.

In the report, "The State of Homelessness in America," even shelters get some of the blame for increasing the number of people who are homeless. The argument: Some people would be able to find their own housing if they were turned away from shelters.

"While shelters play an extremely important role in bringing some people off the streets, it also brings in people who would otherwise be housed, thus increasing total homelessness," the report states.

Los Angeles Mayor Eric Garcetti blasted the report for treating "this crisis like fodder for a cable news debate."

“We don’t have time for that," he said in a statement. "If the president really cares about solving this crisis, he wouldn’t be talking about criminalization over housing. He’d be making dramatic increases in funding for this country’s housing safety net.”

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Homelessness is a national problem, the Trump administration report states, blaming "two decades of misguided and faulty policies" that have left more than 500,000 homeless on a single night in the U.S. About 65% find their way into shelters but the rest live in cars, parks or elsewhere out in the open.

The problem is concentrated on the West Coast and Northeast. About 47% of all unsheltered people in the nation are in California, the report states.

The key issue behind homelessness, according to the report: Housing costs are too high because of overly restrictive zoning, rent control, energy and water mandates, historic preservation requirements and other measures that hold down new construction.

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If such constrictions could be relieved, the ranks of the homeless could fall precipitously, the report predicts. Just by deregulating housing markets in 11 metro areas, overall homelessness would fall 13%, the report claims. In San Francisco, it would plummet 54% and in Los Angeles, 40% – both cities with sky-high rents.

Part of the problem involves policies that allow people to sleep on the streets, the Trump administration says. The report notes some warm-weather cities, like Orlando and Las Vegas, have relatively low rates of unsheltered homeless people. "It is clear that warm climates enable, but do not guarantee, high rates of unsheltered homelessness," it states.

The report says while homelessness should not be treated as a crime, how police approach "street activities" is a factor in how many people are homeless in a city.

Homeless advocates weren't impressed by the report.

The report "reflects a fundamental misunderstanding of homelessness, the programs that end homelessness, and the people who experience it," wrote the National Alliance to End Homelessness in a statement. The report, the group says, brushes aside data on programs that have worked and what communities have learned along the way.

"It is a simplistic response to an extraordinarily complex issue," the group says.

Contributing: The Associated Press