Apple says it's challenging government efforts to overcome encryption on at least 14 devices nationwide in addition to the phone of a San Bernardino, California, shooter.
Lawyers told a New York federal magistrate judge that Apple is opposing relinquishing information on at least 15 devices in court cases in California, Illinois, Massachusetts and New York.
A Feb. 17 Apple court document was unsealed Tuesday. In a court filing, the government says Apple's position has been inconsistent.
Apple attorney Marc Zwillinger said the government has asked it to perform "burdensome and involved engineering'' to circumvent security.
The company's highest-profile fight has been over information on the phone of a San Bernardino attacker.
Apple first challenged the government in October in an otherwise routine drug prosecution in New York.