(CNN)-- US President Donald Trump announced Monday that the United States intends to launch additional military strikes against Iran, indicating further moves after the resumption of negotiations between the two countries last week.

During an interview with conservative radio host Hugh Hewitt, Trump hinted that the United States is closely monitoring Iranian targets but refrained from discussing operational details, saying: "We'll hit them hard tonight, and we'll hit them hard tomorrow."

Hewitt asked whether the US or Israeli military knew the location of the remaining Iranian military leadership and whether they could target it. Trump replied: "Yes, I know, but we don't want to talk about that. But we are definitely monitoring the situation."

The US president described the much-touted memorandum of understanding with Iran as a "test" he would have preferred to avoid, saying: "It's a usual tactic in the United States, where you reach a memorandum of understanding and then an agreement. I said: 'Let's start with the agreement first, but you know, it was kind of a test, and they didn't abide by it. They didn't respect the test.'"

The ceasefire agreement, signed last month, began a 60-day period to negotiate some of the more complex nuclear issues, but the agreement appears to be completely collapsing with strikes resuming from both sides in the region.

Trump had previously described the memorandum of understanding as "an agreement with Iran that achieves everything we sought... ending the current conflict, reopening the Strait of Hormuz, and preventing Iran from obtaining a nuclear weapon," but he said Monday that it "doesn't mean much when you're dealing with corrupt people, and it also doesn't mean much when you're dealing with honorable people, because it's just a memorandum of understanding - it doesn't mean much."

Later, Trump said the United States would eventually take control of the Strait of Hormuz, and insisted that the war is going "very quickly," even as it exceeds deadlines he had previously predicted for its end.

He added, speaking to reporters in the Oval Office: "We will attack them tonight, and we will eliminate all their capabilities related to the Strait of Hormuz, and I think we will eventually take control of everything."

When asked how long he expects the war to last, he said he believes the conflict is moving quickly. In early March, when the conflict was in its early stages, he predicted it would end within 4 weeks, and said: "Well, I think things are going very quickly. We have destroyed their army."