AUSTIN, Texas (AP) — Texas’ plan to arrest migrants who enter the U.S. illegally is headed to the Supreme Court in a legal showdown over the federal government’s authority over immigration.

The high court on Monday blocked Texas’ immigration law from going into effect until March 13.

It asked the state to respond by March 11.

The law was set to take effect Saturday.

The court’s decision came just hours after the Justice Department asked it to intervene. Republican Gov. Greg Abbott signed the law in December.

For months, he’s unveiled a series of escalating measures on the border that have tested the boundaries of how far a state can go keep migrants from entering the country.