DES MOINES, Iowa (AP) — Two organizations are expected to announce a lawsuit challenging a new Iowa law that bans most abortions once a fetal heartbeat is detected.

Iowa affiliates for Planned Parenthood and the American Civil Liberties Union said Monday they’ll make a joint announcement Tuesday afternoon. They declined to provide more information.

The law, set to go into effect on July 1, bans most abortions in Iowa once a fetal heartbeat is detected. That’s around six weeks of pregnancy, making it the strictest abortion regulation in the country.

The groups warned shortly before Iowa Republican Gov. Kim Reynolds signed the law on May 4 that they would challenge its constitutionality. Reynolds and GOP lawmakers with majorities in the Legislature also indicated they expected the law to face litigation.