Under Secretary of State for Arms Control and International Security Thomas DiNanno faced sharp questioning from Democratic lawmakers during recent congressional hearings on Capitol Hill.

DiNanno, who oversees U.S. policy on nonproliferation, arms control, and international security, was testifying under oath about the ongoing war between Israel and Iran.

In the House, Representative Joaquin Castro pressed DiNanno on Israel’s nuclear capabilities as the conflict escalates and both sides have reportedly targeted nuclear-related facilities.

Castro asked: “What is Israel’s nuclear capability in terms of weapons?”

DiNanno replied: “I can’t comment on that specific question. I’d have to refer you to the Israelis on that.”

When pressed further on whether Israel has nuclear weapons, DiNanno repeated: “I’m not prepared to comment on that.”

Castro responded: “You’re the main person in charge of knowing this… We are in a war alongside Israel against Iran. We’re dealing with the potential for nuclear fallout. And you won’t answer this basic question.”

DiNanno stated it was outside his purview as Under Secretary for arms control and nonproliferation.

In a separate exchange, Representative Bill Keating questioned DiNanno about the administration’s approach to Ukraine and Russia, including cuts to support for Ukraine’s prosecutor general who is handling war crimes cases.

Keating asked directly: “Is Vladimir Putin a war criminal, Sir?”

DiNanno responded that the question was outside his purview, adding: “I’m not going to answer yes or no.”

Keating pressed: “As an American person and a citizen?”

DiNanno replied: “I understand that I’m both… I’m not going to answer yes or no.”

The exchanges have drawn criticism from Democrats, who argue the administration is avoiding accountability on key national security issues amid the Israel-Iran war and shifting U.S. policy toward Ukraine.