WASHINGTON (AP) — Sen. John McCain is demanding a full accounting from the Department of Veterans Affairs on the financial status of its private-sector health care program.

The Associated Press reported this week that the Veterans Choice program could run out of money by year's end, despite receiving $2.1 billion in emergency funding last month.

In a letter to VA Secretary David Shulkin, McCain says he wants to know when exactly the VA expects Choice to run out of money. McCain's letter cites AP's report, which included VA's acknowledgment that Choice funds could be depleted as early as December or as late as March.

The Arizona Republican chairs the Senate Armed Services Committee.

Another shortfall could force the VA to limit referrals to outside doctors, causing delays in care for thousands of veterans.