Planned Parenthood said Wednesday it will withdraw from an important government family-planning program on Monday, unless it gets help from a federal appeals court.

The group’s clinics “will be formally out of the Title X program” and lose significant federal funding unless the 9th Circuit Court in San Francisco blocks a new Trump administration “gag rule” barring clinics from referring patients for abortions, reports the Associated Press.

“The gag rule is unethical and dangerous, and we will not subject our patients to it,” said Alexis McGill Johnson, acting president of Planned Parenthood Federation of America, in a statement cited by Vox.

While abortion is legal in the U.S., “federal laws prohibit the use of taxpayer dollars to pay for abortions except in cases of rape or incest or to save the life of the woman,” the AP says.

Johnson calls the Trump administration move “a blatant assault on our health and rights,” and declares: “we will not stand for it.”

Planned Parenthood serves 40% of the country’s 4 million Title X patients, or about 1.6 million Americans.

Unless the court takes action by Monday, Johnson says, “this gag rule will destroy the Title X program — putting birth control, breast and cervical cancer screenings, and STI testing and treatment at risk for millions of people struggling to make ends meet.”

“It’s unclear what the immediate impact would be for patients next week because Planned Parenthood has also pledged to keep its doors open as it contests the administration’s policy change,” says ABC News. “It’s seems likely that any disruptions will vary from state to state.”

The new rule, announced in March, “requires providers that receive Title X funds be both physically and financially separate from any entity that provides or refers for abortions,” Vox says. It adds that providers “were already banned from using Title X money to pay for abortions, but … could still perform abortions if they covered the costs with other funds.”

Planned Parenthood calls the rule both unethical and illegal, since the law requires that Title X patients get “unbiased counseling about all their options for a pregnancy,” Vox says.

In her statement, Johnson writes that Planned Parenthood will seek other funding sources, but “it is unrealistic to think grants or private donations can replace a decades-old federal program.”

Vox notes that “reproductive health advocates” see the Title X rule “as part of a larger attempt by the administration to restrict not just abortion, but contraception as well.”