(AP) — Reproductive rights attorneys say a Mississippi law banning most abortions at about six weeks of pregnancy is unconstitutional and will make the procedure “virtually unavailable” in the state.

In court papers filed Thursday, the attorneys give detailed arguments about why they want a federal judge to block the law from taking effect July 1.

State attorneys said last week that Mississippi has an interest in preserving fetal life “from the moment of conception.”

The Center for Reproductive Rights and the Mississippi Center for Justice are representing Mississippi’s only abortion clinic. They sued the state in March after Republican Gov. Phil Bryant signed a law banning most abortions once a fetal heartbeat is detected, about six weeks into pregnancy.

It is one of the strictest abortion laws in the U.S.