National Security Adviser John Bolton wouldn’t say Sunday whether the United States would sanction European companies that continued doing business in Iran following President Donald Trump’s withdrawal from the Iran nuclear deal.

The United States’ withdrawal has left this an open question: How aggressively will the Trump administration seek to apply sanctions to Europeans and others who have committed to that deal, formally called the Joint Comprehensive Plan of Action?

In his speech announcing the United States’ withdrawal from the deal and re-imposition of sanctions on Iran, Trump said “any nation that helps Iran in its quest for nuclear weapons could also be strongly sanctioned by the United States.”

“Is the United States going to sanction European companies that do business with Iran?” CNN’s Jake Tapper asked Bolton Sunday, referring to Trump’s quote.

Bolton didn’t answer directly, instead saying that Europeans still abiding by the deal may eventually “see that it’s not in their interest to stay in the deal.”

“I think the Europeans will see that it’s in their interest ultimately to come along with us,” he added later.

“I’ve been speaking to European diplomats and that’s not the impression I get,” Tapper replied.

“That’s not the impression now,” Bolton said.

“They say they’re going to stay in the deal,” Tapper said again.

“And they may try to do so,” Bolton said, asserting that many Europeans were “really surprised we got out of it, really surprised at the re-imposition of strict sanctions.”

“I think that will sink in, and we’ll see what happens then,” he said.

Tapper tried again: “Is the U.S. going to impose sanctions on European companies that continue to do business with Iran?”

“It’s possible, it depends on the conduct of other governments,” Bolton said.

But the national security adviser seemed unconcerned at the prospect of losing key allies in future negotiations with Iran.

“The United States imposing economic sanctions is a far cry from the United States and China and Russia and Europe imposing economic sanctions,” Tapper said earlier in the interview. “The U.S. is essentially, at least as of now, going it alone. How will that force Iran back to the table?”

“We are not going it alone,” Bolton replied. “We have the support of Israel, we have the support of the Arab oil-producing monarchies and many others.”