WASHINGTON — The Biden administration on Thursday sued the state of Texas over its new law prohibiting most abortions after the detection of a fetal heartbeat.

In a complaint filed in a federal district court in West Texas, the Justice Department said the state acted “in open defiance of the Constitution” in restricting “most pre-viability abortions.”

The complaint was reported by Bloomberg News.

The Texas Heartbeat Act, S.B. 8, requires doctors to check for a fetal heartbeat before performing an abortion. If a heartbeat is detected — which can be as early as six weeks into pregnancy — the law prohibits abortions except in medical emergencies.

However, the law is enforced through private civil lawsuits and not by the state.

Abortion providers challenged the law in court, but the Supreme Court on Sept. 1 denied their petition to block the law from going into effect.

In response, President Joe Biden called the law “an unprecedented assault on a woman’s constitutional rights,” and promised a “whole-of-government” effort to maintain abortion in Texas.

He directed federal agencies, including the Justice Department, to review what actions could be taken “to ensure that women in Texas have access to safe and legal abortions as protected by Roe.”

Under the Texas law, plaintiffs may not sue women for illegal abortions. They may sue those who perform illegal abortions, and anyone who “knowingly” aids and abets an illegal abortion.

However, the law forbids those who impregnate women who then have abortions from bringing lawsuits in those cases.  

Successful lawsuits can net at least $10,000 in damages under the law, plus court costs and attorney fees.