(CNN) The Democratic leaders of California and New York City are taking steps to provide health care coverage to some undocumented residents.

On his first day in office, California Gov. Gavin Newsom proposed a budget on Monday that would make California the only state in the nation to provide coverage to undocumented young adults through its Medicaid program.

New York City Mayor Bill de Blasio announced an even more ambitious program on Tuesday called NYC Care that would provide coverage for all New Yorkers. There are roughly 600,000 residents without health insurance, half of them undocumented immigrants.

"From this moment on in New York City, everyone is guaranteed the right to health care," said de Blasio, comparing it to the universal pre-K program his administration implemented several years ago.

NYC Care will start rolling out in coming months and will take more than two years to be fully implemented, de Blasio said. It will cost at least $100 million, but the mayor said that the city would save a lot because fewer people would go to the emergency room, which provides pricey and inefficient care.

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