(AP)—Arkansas Gov. Mike Beebe has vetoed legislation that would have banned abortions 12 weeks into a pregnancy.

The Democratic governor on Monday vetoed the bill that opponents say, if enacted, would be the strictest prohibition on abortions in the nation. It would ban abortions 12 weeks into a pregnancy if a fetal heartbeat is detected using an abdominal ultrasound.

The Republican-led Legislature gave the measure final approval last week.

Beebe also had vetoed another measure banning abortions 20 weeks into a pregnancy, but the Legislature overrode that on Thursday.

Beebe has said both measures are unconstitutional and would open the state to .

It takes a simple majority to override a governor's .