Five other states — Illinois, Maine, New York, Oregon and Washington — have similar laws on the books. But HHS is, for now, only singling out California.

California Gov. Gavin Newsom indicated the state won't change the policy.

"The Trump administration would rather rile up its base to score cheap political points and risk access to care for millions than do what’s right," he said. "California will continue to protect a woman’s right to choose, and we won't back down from defending reproductive freedom for everybody — full stop.”

California's Attorney General Xavier Becerra tweeted "California won't be deterred. We will fight this by any means necessary."

The move is in line with other Trump administration actions targeting the progressive state over issues including environmental standards, immigration policies and homelessness. It was also timed to coincide with the March for Life on the National Mall, where President Donald Trump will become the first president to address the anti-abortion demonstration in person as he works to shore up support from social conservatives.

Groups opposed to abortion immediately praised the threat to cut funding.

The Family Research Council said the decision shows "just how seriously this administration views its role in protecting conscience rights for all Americans" while the leader of Susan B. Anthony List — a group that plans to spend tens of millions of dollars this year to help Trump get re-elected — praised him as "the most pro-life president in U.S. history."

While public insurance programs like Medicaid have long been barred from covering abortion services, Friday’s announcement also marks an escalation of the administration’s efforts to extend the prohibition to private coverage. In December, HHS unveiled a rule requiring private insurers on Obamacare markets to send patients separate monthly bills to separate the portion of the premium that goes toward abortion coverage. The added administrative burden could prompt some insurers to drop abortion care altogether.

"We're sending a message that if any state does what California has done, they should likewise expect to be found in violation," Severino said. "Whatever one thinks of the legality of abortion, the American people have spoken with one voice that they should not be forced to pay for, participate in, or cover someone's abortion."

HHS said a Catholic order that previously and unsuccessfully sued California over the policy — the Missionary Guadalupanas of the Holy Spirit — filed a complaint with the Office for Civil Rights that led to the investigation and notice of violation. Severino on Friday compared the issue to the legal challenge filed by another group of nuns challenging the Obamacare's birth control mandate — a case the Supreme Court last week agreed to review.

"The parallels with the Little Sisters of the Poor case are clear," he said. "Once again, the government is trying to force nuns to cover abortion for fellow nuns. Why can't they be left alone?"

