Donald Trump addresses a rally against the Iran nuclear deal on September 9, 2015 in Washington, DC | Chip Somodevilla/Getty Images Donald Trump won’t rule out using nukes in Europe ‘I am not taking cards off the table,’ the Republican presidential hopeful said.

The option of using nuclear weapons, either in the Middle East or Europe, should never be taken off the table, Donald Trump said Wednesday.

During a town hall meeting in Wisconsin, MSNBC's Chris Matthews asked Trump, on a quest to become the Republican presidential candidate, if he could rule out the use of nuclear weapons in Europe.

“I’m not going to take it off the table,” Trump said. When Matthews asked again whether Trump might use nuclear weapons in Europe, the real estate mogul responded: “No. I don’t think so, but … I am not taking cards off the table.”

Trump has previously sent mixed signals on the issue.

He told The New York Times over the weekend that nuclear proliferation is the world's "biggest problem," but later told CNN that "maybe it's going to have to be time to change" U.S. policy that prevents Japan and South Korea from having nuclear weapons.

"We're better off if Japan protects itself against this maniac in North Korea, we're better off, frankly, if South Korea is going to start to protect itself," Trump told CNN.

When Matthews suggested Wednesday that no one wants to hear a potential U.S. president talking about using nuclear weapons, Trump responded: "Then why are we making them?"