Parents of unvaccinated children in New York state gathered in Albany Monday to protest the repeal of a religious exemption to school immunization requirements.

Hundreds of people carrying signs and dressed in white assembled in front of the state education building Monday to urge state school officials to delay the elimination of the exemption and let their children return to school.

Lawmakers voted to eliminate the religious exemption in June, amid the nation's worst measles outbreak in decades. The new law gives unvaccinated students up to 30 days after they enter a school to show they've had the first dose of each required immunization.

New York still provides an exemption to the rules for children who cannot get immunized for medical reasons, such as a weakened immune system.

Some parents at Monday's protest said the new law may force them to homeschool their children or move out of New York. Monday's event was timed to coincide with a meeting of the state's Board of Regents, which oversees educational policy but had no role in the repeal of the exemption.

"This is about religious freedom," said Devin Fricano, who lives in the state's Finger Lakes region and whose 10-year-old daughter is unvaccinated. He said his family has religious objections to vaccinations, as well as concerns about their health effects.

Opponents have also filed legal challenges seeking to block the change.

State leaders have stood by the repeal, arguing that religious beliefs about vaccines shouldn't outweigh evidence that they work.

"This law will help protect New Yorkers from experiencing any additional public health crises, which is why we vigorously defended it," state Attorney General Letitia James said in a statement last month.

The U.S. Supreme Court ruled in 1905 that states have the right to enforce compulsory vaccination laws.

California removed personal belief vaccine exemptions in 2015. Maine ended its religious exemption earlier this year. Mississippi and West Virginia also do not allow religious exemptions.