State senators on Tuesday approved a bill that would make juveniles convicted of first-degree murder eligible for parole after serving between 20 and 30 years in prison.

Amendments that would have raised the minimum threshold for parole to 35 years or to 25 years were defeated, the latter by a single vote.

The bill represented the latest effort by lawmakers to reconcile Massachusetts law with rulings by the U.S. Supreme Court and the state's highest court that said mandatory life sentences without parole for juveniles was unconstitutional

Under the measure, teens convicted of first-degree murder before their 18th birthday eligible would become eligible for parole after serving at least 20 years, but not more than 30 years. Senators did approve one amendment requiring the full 30-year wait for murders committed with extreme cruelty.