WASHINGTON — The prospect that the federal government will suspend processing of immigrant work visas has rural health systems in Minnesota and the Dakotas scrambling to protect doctors already working in or bound for rural, underserved areas.

Dakotas-based Sanford Health, which also operates hospitals and clinics up and down western Minnesota, is rushing to complete visa petitions for immigrant doctors whose plans to practice in the region this summer have been upended by a heavy backlog of cases at U.S. Citizenship and Immigration Services (USCIS).

The agency has said it will suspend expedited processing of certain immigrant work visas for six months starting in April, worrying rural health advocates and immigration attorneys around the country, and leaving foreign doctors scrambling about how they'll stay in America.

"These programs have filled important gaps in rural communities," said Cindy Morrison, chief marketing officer of Sanford.

She added that if the doctors' petitions aren't approved quickly, it will be difficult to find people to carry out their duties, particularly because many are in specialties such as gastroenterology and hematology. Other Sanford doctors could pick up more hours to offset the vacancies, which Sanford doesn't consider a long-term solution, and hiring temporary replacements is expensive.

Sanford and other hospital organizations pay the government $1,225 to provide "premium processing" of a type of work visa called the H-1B, a service that can grant international medical students approval in just a few weeks, instead of as long as eight months.

Citizenship and Immigration Services announced it would suspend the premium processing service as of April 3 after experiencing a large increase in requests. The volume of such filings was 61 percent higher in the 2016 fiscal year compared to two years earlier, according to spokeswoman Mirilu Cabrera. She said premium processing filings of H-1B petitions now account for 59 percent of the total filings of that visa category.

Cabrera said the agency couldn't give specific numbers on the backlog, but processing times for H-1B petitions had grown to more than eight months in California and more than 11 in Vermont.

Rural health advocates said they were especially worried about the suspension's effects on a program that waives a requirement for foreign doctors to return to their home countries for two years after completing medical training here. That program, named for former North Dakota Senator Kent Conrad, allows 30 such physicians in each state to stay in the U.S. if they agree to serve in rural or otherwise medically underserved communities.

Minnesota has 120 physicians working under the so-called Conrad 30 program, according to Mark Schoenbaum, director of the state's Office of Rural Health and Primary Care. He said the greatest proportion of foreign-trained physicians work in southwest Minnesota.

Now those in rural healthcare say there's an overall climate of uncertainty sweeping immigrant doctors.

"People begin to worry if they're in medical school outside the United States if they should consider coming here for medical residency to make their careers," said Schoenbaum.

Minneapolis-based immigration attorney Sarah Peterson said the agency proposed this suspension to eradicate one problem — the backlog — but is simply creating another problem.

"People are panicking," she said. "They aren't sure if they need to make travel plans to leave the United States because they don't know."

She said the agency could have addressed its delays in a way that would have offered visa petitioners more security. Now she speaks regularly with employers and employees "who are incredibly stressed out and worried. They can't focus on their training or work because it's so unpredictable."

Physicians affected by the suspension were planning to start their new jobs in July.

Sanford has 14 doctors who have just finished their training visa and wanted to move to the H1-B visa to follow through on plans to start medical jobs. The company is hurrying to process another 36 doctors whose visas will need to be renewed during the suspension period.

Minnesota U.S. Sen. Amy Klobuchar recently joined Sen. Heidi Heitkamp of North Dakota and Sen. Susan Collins of Maine in urging USCIS to address its administrative needs without pausing the expedited processing of visas. In an interview, Klobuchar said she hasn't heard back from the agency but plans to introduce legislation soon to address the suspension. She noted that a lot of rural states with Republican senators rely on the program.

"We'd like to expand the program," Klobuchar said.

Peterson she's glad to see a bill introduced, but doesn't think it would move fast enough to stop many immigrant doctors from landing in limbo.

Immigration attorney Elise Bruner said her Minneapolis office has "stacks and stacks" of petitions from clients who want to file for premium processing before the deadline. She's worried about communities on the Iron Range and in northwestern Minnesota that rely on immigrant doctors, especially given their aging populations.

She said the temporary suspension has taken people off guard because while there had been delayed visa processing before, there have never been such broad suspensions.

"This is a severe impact," said Bruner.