In remarks Tuesday before the Council on Foreign Relations, Seidenberg cited a recent Wall Street Journal report that said Apple is working on a version of the iPhone that would be compatible with Verizon's network.
But he did not confirm the report or give any further details Tuesday.
AT&T Inc. has exclusive rights to the iPhone in the United States. The company has been silent about the reports on the new iPhone model.
Apple is expected to announce details on a new iPhone operating system Thursday in Cupertino, Calif.