WASHINGTON (JTA) — A bipartisan group of 10 U.S. Senate leaders urged President Obama to make sure that Iran’s public remarks on its nuclear program match its actions.

In their letter released to the media on Monday, the senators also said the president should continue with diplomatic efforts aimed at stopping Iran from obtaining nuclear weapons.

The letter, which was backed by the American Israel Public Affairs Committee, was sent ahead of upcoming talks in Geneva between Iran and six world powers — the United States, Russia, China, the United Kingdom, France and Germany.

“We support your efforts to explore a diplomatic opening, but we believe that the true test of Iranian sincerity is a willingness to match rhetoric with actions,” the senators wrote.

Iran must fully cooperate with the International Atomic Energy Agency and fulfill its responsibilities under the Nuclear Nonproliferation Treaty, as well as implement all resolutions passed by the United Nations Security Council concerning its nuclear weapons program, the letter said.

It added that if Iran takes the necessary steps “in a verifiable and transparent manner, we are willing to match Iran’s good-faith actions by suspending the  implementation of the next round of sanctions currently under consideration by the Congress.”

The senators reiterated that military action was still possible.

Sens. Robert Menedez (D-N.J.), Lindsey Graham (R-S.C.), Charles Schumer (D-N.Y.), Roy Blunt (R-Mo.), Patty Murray (D-Wash.), John McCain (R-Ariz.), Barbara Mikulski (D-Md.), Kelly Ayotte, (R-N.H.), Robert Casey Jr. (D-Pa.) and Christopher Coons (D-Del.) signed the letter.