U.S. Reps. Keith Ellison, D-Minn., and Walter Jones, R-N.C., have, for several weeks, been circulating a letter they wrote to President Barack Obama, urging him to find a peaceful solution to the crisis over Iran's nuclear program.

"While we acknowledge that progress will be difficult , we believe that robust, sustained diplomacy is the best option to resolve our serious concerns about Iran's nuclear program and to prevent a costly war that would be devastating for for the United States and our allies in the region," the letter reads, in part.

President Obama has said that the United States would consider attacking Iran if the country builds a nuclear weapon, but cautioned Israel -- a U.S. ally -- that a premature attack on Iran would do more harm than good.

Obama will address the American Israel Public Affairs Committee (AIPAC) on Sunday and meet with Israeli Prime Minister Benjamin Netanyahu on Monday at the White House.

AIPAC is influential in Washington, D.C., on behalf of Israel's interests and frequently sponsors congressional trips there. The American Israel Educational Foundation, privately funded lobby affiliated with AIPAC, frequently pays for members of Congress to travel to Israel. Ellison has traveled there in 2007 and Sen. Al Franken just returned from a trip last month.

Ellison and Jones are urging their colleagues in Congress to forward the letter to President Obama to, in their words, "redouble our diplomatic efforts to achieve the transparency measures that will ensure Iran's nuclear program remains a civilian one."

Here are copies of the letters to Congress and President Obama:

Ellison Letter