WASHINGTON — Secretary of State John Kerry tried to lower the temperature on Sunday in the three-way fight among congressional Republicans, the Obama administration and Prime Minister Benjamin Netanyahu of Israel, saying that Mr. Netanyahu was welcome to speak in the United States.

But Mr. Kerry also said that it was “odd, if not unique” that the administration learned of the Israeli leader’s coming address to Congress not through diplomatic channels, but from Speaker John A. Boehner, Republican of Ohio, and that the “administration was not included in the process.”

Mr. Kerry’s comments, on the ABC program “This Week,” were the latest salvo in the escalating back-and-forth over Mr. Netanyahu’s decision to accept the invitation from congressional Republicans to speak on Tuesday about his concerns over negotiations with Iran on its nuclear program.

Mr. Netanyahu is expected to criticize an emerging agreement that many in Israel fear will leave Iran with a substantial infrastructure with which to pursue the development of nuclear weapons when the accord expires. But many Obama administration officials believe the negotiations could lead to one of the president’s most significant foreign policy achievements.