WASHINGTON: The US will respond firmly if Iran fails to honor the accord aimed at curbing its nuclear program, President Barack Obama said Friday, as he works to win over undecided US lawmakers.

“We have a wide array of unilateral and multilateral responses that we can employ if Iran fails to meets its commitments,” Obama said in a letter dated Aug. 19 and sent to Jerrold Nadler, a Democrat in the House of Representatives who announced that he will vote to approve the accord.

In his letter released by the White House, Obama reiterated his view that the accord reached last month in Vienna is good for the United States, Israel and the Middle East in general.

The president also insisted, as he has many times, that all options remain on the table if Iran does not abide by the accord.

The agreement lifts economic sanctions against Tehran in exchange for restrictions and other measures designed to prevent it from developing nuclear weapons.

“All of the options available to the United States — including the military option — will remain available through the life of the deal and beyond,” Obama said.

The letter was released as opponents of the accord wage a fierce campaign against it ahead of a vote in Congress in September.