Sens. Bernie Sanders and Elizabeth Warren teamed up with Rep. Ayanna Pressley on Thursday to lead nearly 90 lawmakers in demanding that Congress extend federal funding for Community Health Centers before it expires next month.

Allowing a lapse in CHC funding would imperil crucial health services for "28 million patients, including over 350,000 veterans, over eight million children, and 1.4 million homeless patients" across the country, the lawmakers warn in a letter (pdf) to congressional leaders.

"We believe that Congress must immediately secure additional funding for these critical public health programs and urge swift action before November 21 to ensure continuous access to medical training and healthcare services for all who need it," the members of Congress write.

To ensure health centers are adequately funded, the lawmakers are calling on Congress to provide a five-year extension of CHC funding in line with legislation introduced in March by Sanders and Rep. James Clyburn (D-S.C.). Under the Sanders and Clyburn bill, CHCs and the National Health Service Corps would receive a 10 percent increase in funding annually for five years.

"It is no exaggeration to call Community Health Centers a lifeline for millions of Americans," Sanders, who has played a major role in securing funding for CHCs over the past decade, said in a statement on Thursday.

"President Trump and the Republicans tried and failed to destroy the Affordable Care Act in Congress. Now they're in the courts still trying to kick millions off their health care. We are standing together to push back on this relentless assault on people’s basic health," the Vermont senator added. "Congress must expand—and not allow any cuts to—the comprehensive medical treatment that so many millions of people depend on through community health centers."

Read the full letter: