Protesters on both sides of the abortion issue gather in front of the U.S. Supreme Court building during the Right To Life March, on January 18, 2019 in Washington, DC.

A divided U.S. Supreme Court on Thursday stopped a Louisiana law imposing strict regulations on abortion clinics from going into effect in its first major test on abortion since the retirement of Justice Anthony Kennedy last summer.

The court on a 5-4 vote granted an emergency application by Shreveport-based abortion provider Hope Medical Group for Women to block the Republican-backed law from going into effect while litigation continues.

The four liberal justices were joined by conservative Chief Justice John Roberts in the majority, suggesting that Roberts, as Kennedy used to be, is now the key vote on the issue.

Kennedy backed abortion rights in two key cases. Justice Brett Kavanaugh, who President Donald Trump appointed to replace Kennedy, joined the court's four other conservatives in dissent.

Hope Medical Group challenged the law's requirement that doctors who perform abortions must have an arrangement called "admitting privileges" at a hospital within 30 miles (48 km) of the clinic.

The court on Feb. 1 temporarily blocked the law, which was due to go into effect on Feb. 4, while the justices decided how to proceed.

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