FBI Director James Comey says the issues raised in the Justice Department's dispute with Apple Inc. represent the "hardest question I've seen in government."

Comey was appearing Thursday before the House Intelligence Committee, a week after a California judge ordered Apple to help the FBI hack into a locked iPhone used by one of the gunmen in last year's San Bernardino mass shooting.

Apple is expected to file an objection by Friday.

Comey says the central question is "who do we want to be, and how do we want to govern ourselves."

He says Apple had been "very cooperative" in the dispute and that there have been "plenty" of negotiations between the two sides.