Obama administration officials are promising a major strengthening of U.S. defense commitments to Saudi Arabia and other Persian Gulf allies, possibly including a nuclear commitment to their security, in an intensifying effort to win their support for the proposed nuclear deal with Iran.

Officials say they hope to reassure nervous gulf Arab states by providing more military aid and training to their defense forces, and by making more explicit commitments to help them repel external attacks.

The administration is studying whether to make any nuclear assurances, though officials emphasize no decision has been made. […]