The Centers for Medicare and Medicaid Services on Friday provided advanced notice to insurers about proposed cuts in Medicare Advantage payments in 2015 as part of President Obama's health care law.

Medicare Advantage is a program that offers privately administered insurance options to Medicare beneficiaries. About 15 million Americans, or nearly 30 percent of all Medicare beneficiaries, are covered through a Medicare Advantage program.

Cuts to Medicare Advantage payments made to private insurers were among the major ways that Democrats financed Obamacare. The cuts are one of many aspects of Obamacare that put pressure on health care access, because insurers that are receiving less money from the government cannot offer as broad a choice of medical providers to their beneficiaries.

In the latest guidance issued late Friday, CMS said that Medicare Advantage payments would shrink by 3.55 percent in 2015, which the agency touted as a smaller cut than last year.

Republicans immediately sought to capitalize on the news.

"Today millions of U.S. seniors, including thousands in my own congressional district, are joining the ranks of those betrayed by the empty promises of the president's health care law," House Speaker John Boehner said in an emailed statement. "The result of this action represents another broken promise by the president and another breach of trust with the American people by the Democrats who run Washington."