CIA officers at the U.S. embassy in Lebanon have recruited low-level members of Hezbollah to spy for Israel, the leader of the Iranian-backed militant group charged Friday.

It was the first time Hezbollah has acknowledged that spies had penetrated the militant group, a rare acknowledgment of a security breach for a group that has tried to assert a powerful and cohesive image.

In a televised speech, Sheik Hassan Nasrallah said the development puts the Shiite group "in front of a new stage of security struggle."

Nasrallah said the CIA recruited at least two Hezbollah members and the group was investigating whether the CIA or another foreign agency recruited a third.

"We now have proof in our hands that this embassy is a spying nest," he said.

Israeli Foreign Ministry spokesman Yigal Palmor said he "would not dignify" the accusations with a comment. The U.S. Embassy did not immediately respond to a request for comment.

Nasrallah did not name the suspects, saying he wanted to protect their families "whom I know personally." All three confessed their actions to a Hezbollah "spy combat unit," he said.

Nasrallah added that none of the men had any sensitive information about the group.

Hezbollah and Israel fought a devastating, 34-day war in 2006 that that left 1,200 Lebanese and 160 Israelis dead.

Nasrallah's accusations come at a tumultuous time in the Middle East and illuminate how Hezbollah's web of allegiances and enemies touch on many of the region's most explosive conflicts.

"We had assumed that we were in security confrontation with the Israelis ... but to become a direct target for U.S. intelligence like this, this undoubtedly puts us in front of a new stage of security confrontation," Nasrallah said.