In the latest salvo from the Trump administration to crack down on “sanctuary cities,” the country’s top cop on Monday said he will withhold billions of dollars in law enforcement grants as leaders across the state and nation remained steadfast in their refusal to turn over illegal immigrants to federal agents.

“This is the same old extortion attempt that they’ve been pushing, and it’s the worst kind of pressure,” said Santa Clara County Board President Dave Cortese, who is in New York City discussing defense strategies against the immigration crackdown with other top officials. “Everyone here is in complete solidarity — Baltimore, Philadelphia, New York City, everyone is on board — and the Trump administration’s got a real fight on their hands.”

Santa Clara County was a leader in that fight when it filed a lawsuit last month challenging the constitutionality of withholding federal funds in response to an earlier threat from the Trump administration, which Attorney General Jeff Sessions ratcheted up on Monday. The lawsuit has since been joined by dozens of cities and counties.

At the state level, California Attorney General Xavier Becerra said Trump’s administration should “rethink its plan to force state and local governments to do the federal government’s bidding on immigration.”

“It’s a low blow to our brave men and women in uniform,” Becerra said, “to threaten to withhold public safety funding that they have earned unless Donald Trump gets his way on immigration.”

But Sessions said in a press conference that “this disregard for the law must end,” referring to the failure of previous demands for compliance. “I am urging states and and local jurisdictions to comply with the federal laws” to be eligible for grants from the Justice Department.

He warned the nation’s states and cities “to carefully consider the harm they are doing to their citizens by refusing to enforce our immigration laws.” He offered no specifics on what such compliance would entail, but said they would take “all lawful steps to claw-back” money already awarded to non-compliant cities.

Sessions’ threat seems to have more teeth than earlier administration threats to withhold federal funds from sanctuary providers but it involves less money — Justice Department grants make up a small part of the total federal funds doled out. Still, it could hurt various programs, especially in Bay Area counties such as Alameda that rely on federal grants to fund programs for victims of domestic violence and human trafficking. At the state level, however, out of $105 billion coming from the feds, about 80 percent is related to health care, mostly in Medi-Cal payments.

In Santa Clara County, where federal funds add up to about $1.7 billion annually, Cortese said there’s “not a lot of exposure” from this particular threat.

“These are things that we can self-fill if we need to,” said Cortese, who added that it was boggling that the first target would be Justice Department grants. “Taking away money for public safety, of all things. That’s what the administration is supposed to be all about.”

Alameda County Sheriff’s spokesman Sgt. Ray Kelly said that such cuts — which he estimated would total about $15 million in his jurisdiction — would hurt some of the department’s most productive, well-intended programs.

“We’re talking prevention programs for youth — boxing, soccer, fitness, after-school tutoring,” he said. “All that stuff makes a huge difference in the lives of kids — they’ll be less likely to go out and do drugs or join a gang. It’s very frustrating.”

The Bay Area has a number of sanctuary counties including San Francisco, Santa Cruz and Alameda, as well as cities such as Oakland and San Jose. While Santa Clara County has never officially designated itself as a sanctuary, supervisors have said since 2011 they would not cooperate with so-called ICE holds, which stipulate that a county that has an illegal immigrant in custody must turn that person over to federal authorities.

The Trump administration isn’t the first to threaten local agencies over sanctuary rules — the Obama administration told cities they risked losing grant money in 2017 if they didn’t comply with federal law. But now it comes from an administration that has been much more aggressive in moving forward with a crackdown.

Sessions said that grants totaling about $4.1 billion are at stake. The message came a week after the Department of Homeland Security released the first in a weekly “Declined Detainer Outcome Report,” a list of jurisdictions that have not complied with ICE requests. Santa Clara and Alameda counties both made the list with a single case each.

State Sen. Joel Anderson, a Republican from San Diego County, said Sessions’ announcement shows the real repercussions of noncompliance with immigration authorities, and highlights his concerns about a statewide “sanctuary state” bill that’s in the works in Sacramento, which would forbid local police from certain communication with immigration agents.

“This is very serious,” he said. “We’ve been talking in the abstract. This removes doubt. This is real pain. This is fewer officers on the street, no doubt about it.”

But State ​Senate ​President Pro Tem​ Kevin de Leon​, D-Los Angeles,​ ​blasted Sessions’ Monday announcement, saying it​ was “nothing short of blackmail.”

“Instead of making us safer, the Trump administration is spreading fear and promoting race-based scapegoating​,” the Senate leader said in a statement Monday.​ ​​”Their gun-to-the-head method to force resistant cities and counties to participate in Trump’s inhumane and counterproductive mass-deportation is unconstitutional and will fail.”