"We still believe that the best way to prevent escalation, to prevent another front from opening up in Lebanon, is through diplomacy," Kirby said.

Iran, which supports Hezbollah, had held back from major retaliation after an attack inside Tehran that killed the visiting political leader of Hamas.

Israel has been engaging in regular skirmishes with Hezbollah since the October 7 attack by Hamas, also backed by Iran's clerical state.

Asked if Israel was adhering to international humanitarian law in the blasts on pagers and walkie-talkies in Lebanon, Kirby replied: "As we have said from the very beginning, Israel has a right to defend itself."

"How they do so matters to us, and we don't shy away from having those kinds of conversations with the Israelis as appropriate," he said, without confirming Israeli involvement.

As for the United States, Kirby echoed previous statements denying involvement: "We were not involved in yesterday's incidents or today's in any way."