Mr. Reid, a strong supporter of Israel, said in an interview that he had had a candid conversation with Mr. Netanyahu. He said he had advised the prime minister that the speech, scheduled for March, had become such a problem that some Democratic senators had backed off their support of the quick imposition of new sanctions on Iran.

“It’s hurting you,” Mr. Reid said he told Mr. Netanyahu. “I said: ‘You have to understand this. I’m not telling you what to do or what not to do, but you have to understand the background here from my perspective.’ ”

“It would have been wrong for me to say, ‘Don’t come,’ ” said Mr. Reid, who is recovering at his home in Washington from a serious exercise accident he sustained Jan. 1. “I wouldn’t do that.”

Ms. Pelosi said late Wednesday that when she spoke with the prime minister, she had stressed that the speech “could send the wrong message in terms of giving diplomacy a chance.”