The Maryland Senate is scheduled to take up a gun-control measure supported by Democratic Gov. Martin O'Malley.
The bill is set to come before the heavily Democratic chamber on Tuesday, but it's unclear when senators will vote.
Opponents who say the measure violates Second Amendment rights have pledged to seek a variety of amendments. Supporters say it will give Maryland some of the strongest laws in the nation to help prevent gun violence.
One of the most contentious provisions would require people to submit fingerprints for handgun licensing. Supporters say that will make it harder for people to get others to buy guns for them illegally.
The bill also would ban assault weapons and prohibit people who have been involuntarily committed for mental health reasons from owning guns.