Donald Trump's stance on nuclear weapons, including possibly using them on Europe is "bluntly irresponsible and is detrimental to our internal allies security posture," Energy Secretary Ernest Moniz said Thursday.

The energy secretary was speaking to MSNBC's Andrea Mitchell Thursday from the 2016 Nuclear Security Summit in Washington, D.C., when he was asked about comments Trump had made during MSNBC's town hall Wednesday night. In that interview with Chris Matthews, Trump said he "would never take any of my cards off the table," including using a nuclear weapon in the Middle East or in Europe.

The comments are "extremely troubling, obviously," Moniz said.

"We are trying to work to reduce nuclear weapons. Their footprint. We in the United States with Russia have made significant cuts in the arsenal. The president has talked about trying to go further. Ultimately, going to the goal of ideally, a nuclear-free world. Nuclear weapon-free world," Moniz said.