ALBUQUERQUE, N.M. (AP) — Officials at a Veterans Affairs medical center in Albuquerque say as many as 3,000 patients were assigned to a doctor who didn't actually see them, a New Mexico congresswoman said Wednesday.

The officials told U.S. Rep. Michelle Lujan Grisham, D-N.M., that the practice of putting patients without primary care doctors into a separate pool was part of an effort to balance demand and a shortage of doctors at a facility that handled nearly 660,000 outpatient visits last year.

They said the health of patients was monitored and those who needed urgent care were seen either in clinics, emergency rooms or squeezed onto the schedule of another doctor, but it wasn't immediately clear whether the practice put any veterans at risk.

It also wasn't clear how long they waited to be assigned to a doctor. Officials said the practice began in summer 2012 and lasted until January 2014, but they have not said what prompted the end of the program.

The congressional staffers were told nearly two-thirds of patients at the Albuquerque VA medical center are seen within a 14-day window, but Lujan Grisham questioned the data given that VA officials weren't initially forthcoming about the patient pool.

The disclosure of the separate patient pool, which was managed though the local VA's computer system, comes as the Veterans Affairs Department grapples with allegations that secret waiting lists and delayed care sometimes led to the death of veterans in other states.

The congresswoman said she has asked for more information from VA officials, including the results of an internal review. "We want everything, and I don't think we should stop until there's no stone left unturned," she said.

A VA spokeswoman didn't immediately return messages seeking comment Wednesday.

The Albuquerque Journal first reported on the practice by the Albuquerque medical center last week.

The scrutiny began after a federal investigation into the troubled Phoenix VA Health Care System found that about 1,700 veterans in need of care were "at risk of being lost or forgotten" after being kept off an electronic waiting list.

Details about scheduling problems at other VA facilities have continued to surface since the investigation began. The probe has found widespread problems throughout a health care system that provides medical care to about 6.5 million veterans annually.

An official with the VA medical center in Wichita, Kansas, said Wednesday that 385 veterans appeared on an unauthorized list of those waiting for care and an unknown number of those veterans waited longer than 90 days for treatment.

The VA maintained 10 secret waiting lists of veterans seeking care at facilities in Kansas, Missouri, Illinois and Indiana, according to VA letters released this week. The letters also said at least 96 veterans waited more than 90 days for treatment at seven facilities in those states.

Regarding health care delays in southwestern Illinois, U.S. Rep. John Shimkus said officials had assured him last week there were no scheduling delay problems. The Republican said Wednesday he surprised to learn otherwise this week. A development, he said, that "raises more questions."

Lujan Grisham said she was dismayed to learn of the separate patient pool a week after meeting with local officials and being assured there were no secret waiting lists or other practices that would affect veterans' access to care.

She said it will be difficult for the VA to rebut the presumption that information about the patient pool was purposely hidden.

New Mexico VA officials told congressional staffers during a conference call Friday that the practice wasn't intended to hide patients but rather to keep track of them until they could be assigned a primary care doctor. It made it appear the veterans had a primary care physician when they didn't.

The medical supervisor assigned to the patient pool didn't see patients but was available by phone.

"That's not the same as a primary care appointment," Lujan Grisham said. "I don't agree that's fair access."

Among the things Lujan Grisham is trying to find out is how many calls the medical supervisor handled, whether that information made it into the veterans' medical records and if serious cases were reassigned to doctors who could see the patients.

James Robbins, interim director of the New Mexico Veterans Affairs medical center, told congressional staffers during last week's briefing he only learned of the practice recently, according to Lujan Grisham's office.

The New Mexico VA website lists more than 480 doctors, dentists, nurses and other licensed practitioners.