President Donald Trump on Monday said that the U.S. would take out Pickaxe Mountain in Iran, as he warned that Washington would continue to hit the country hard.

“We’re going to take out Pickaxe Mountain. Tell the Iranians to be ready,” Trump said in an interview on the Hugh Hewitt Show.

“We’re watching (Pickaxe Mountain) closely. We see no activity there. They’re not doing well with their nuclear situation. Every time we hear about it, we blow it up. So they don’t like talking about it. But we’ll probably give Pickaxe a shot relatively soon,” Trump said.

Pickaxe Mountain, located near Iran’s heavily damaged Natanz uranium enrichment facility, is a heavily fortified site that hosts two deeply buried tunnel complexes that experts assess as beyond the reach of the most powerful bunker buster bombs in the U.S. arsenal.

Trump earlier on Monday said the United States was reinstating its blockade of Iranian shipping in the Gulf and would ensure the Strait of Hormuz stays open — for a fee — after the two sides exchanged more missile and drone attacks.

“We’re going to hit them very hard tonight and we’re going to hit them hard tomorrow. And there’s not a damn thing they can do about it,” he said on the Hugh Hewitt Show.

(Reporting by Ismail Shakil, Daphne Psaledakis, Christian Martinez and Jonathan Landay; Editing by Caitlin Webber and Michelle Nichols )