The classified intelligence that President Trump disclosed in a meeting last week with Russian officials at the White House was provided by Israel, according to a current and a former American official familiar with how the United States obtained the information.
The revelation adds a potential diplomatic complication to the episode.
Israel is one of the United States’ most important allies and a major intelligence collector in the Middle East.
The revelation that Mr. Trump boasted about some of Israel’s most sensitive information to the Russians could damage the relationship between the two countries.
It also raises the possibility that the information could be passed to Iran, Russia’s close ally and Israel’s main threat in the Middle East.
Israeli officials would not confirm that they were the source of the information that Mr. Trump shared.
In a statement emailed to The New York Times, Ron Dermer, the Israeli ambassador to the United States, reaffirmed that the two countries would maintain a close counterterrorism relationship.
“Israel has full confidence in our intelligence-sharing relationship with the United States and looks forward to deepening that relationship in the years ahead under President Trump,” Mr. Dermer said.