WASHINGTON - President Donald Trump on Monday accused Iran of repeatedly lying and said he’s gotten less interested in negotiations to replace the nuclear deal that he pulled the United States out of last year.

In an exchange with reporters in the Oval Office, Trump was asked about Iran’s statement that it arrested 17 Iranian nationals recruited by the Central Intelligence Agency to spy on the country’s nuclear and military sites.

“That’s totally a false story. That’s another lie,” Trump said.

In Tehran, an Iranian intelligence official told a news conference that the arrests took place over the past months, and that the people taken into custody worked on “sensitive sites” in the country’s military and nuclear facilities.

Trump said Iran also lied about losing a drone that he earlier announced had been destroyed by a U.S. warship near the entrance to the Persian Gulf. Trump said Iran has “disrespected” the United States, and he called it a “very mixed up country” with big economic problems and a restive population.

“They have a lot of problems,” he said. “So, whatever it is, I’m just going to sit back and wait” to see whether Tehran is going to agree to negotiate limits on its nuclear program and other activities.

“If they want to make a deal, frankly it’s getting harder for me to want to make a deal with Iran because they’ve behaved very badly. They’re saying bad things.”

Critics say Trump’s decision to pull out of the 2015 nuclear deal negotiated by former President Barack Obama, as well as his doubling down on economic sanctions, have set the stage for Iran to lash out at the West and make threats short of triggering a war.

Tensions escalated on Friday when Iran seized a British-flagged oil tanker in the Strait of Hormuz. On Monday, British Foreign Secretary Jeremy Hunt accused Iran of “an act of state piracy” that he said must be met with a co-ordinated international reaction.

In Oval Office his comments, Trump also claimed “there’s a lot of proof” that the Navy destroyed an Iranian drone last week over the Strait of Hormuz, although the U.S. actually has provided no public evidence, let alone proof. Iran denied it lost a drone.

The president appeared to confirm news reports that the USS Boxer used an electronic jamming device to bring down the drone, rather than shoot it down with a missile or another conventional weapon.

“The drone came down, you know how it came down, with a new technology that’s actually quite amazing,” Trump said. The U.S. military last week refused to say what kind of weapon it used against the drone.