SANTA FE, N.M. (AP) — A standoff over millions of dollars in insurance premium taxes escalated on Tuesday between New Mexico's attorney general and the state's largest health-care insurance provider.

New Mexico Attorney General Hector Balderas renewed accusations that a for-profit insurance arm of Presbyterian Healthcare Services used an illegal accounting procedure to avoid paying millions of dollars in taxes and surcharges on insurance premiums.

The insurance subsidiary, Presbyterian Health Plan, denied that it owes the state of New Mexico additional premium taxes in new court filings this w...