WASHINGTON – Iran’s claim that it arrested 17 spies recruited by the Central Intelligence Agency further enflamed tensions in the Middle East that have been escalating for months.

Iran's semi-official Fars news agency announced the arrests Monday but gave few details. The Trump administration said the report is false.

Here’s what we know:

What happened?

The Fars news agency said 17 spies had been taken into custody and claimed that some of them already have been sentenced to death.

The arrests reportedly occurred over the past few months, and those taken into custody worked on “sensitive sites” in the country’s military and nuclear facilities, an Iranian intelligence official told a press conference in Iran.

He did not elaborate and did not say how many of them were sentenced to death or when the sentences were handed down. It was not clear if all them were Iranian nationals.

Fars published images that Iran's Intelligence Ministry said showed the CIA officers who it claimed were in touch with the suspected spies.

Drone:Iran says U.S. may have shot down its own drone by mistake

Is it true?

The Trump administration says no.

President Donald Trump called the claim “totally false. Zero truth.”

Secretary of State Mike Pompeo, a former CIA director, also dismissed the report in an interview with Fox News. "The Iranian regime has a long history of lying," he said.

Why would Iran lie?

Tensions between the U.S. and the Middle Eastern country have been on the rise following Trump’s withdrawal last year from a 2015 nuclear agreement negotiated by Trump’s predecessor, Barack Obama, and other world leaders.

The Trump administration slapped new sanctions on Iran in June for what it said was a series of aggressive acts by Tehran, including the downing of U.S. drones. The order targeted Iran’s supreme leader, Ayatollah Ali Khamenei, and those close to him by denying them access to certain financial resources. The measures also block transactions involving any property or other assets Iran's leaders hold in the US.

Trump claimed Monday that Iran’s economy is “dead” and vowed it would “get much worse.”

U.S. seeks assistance:'Work with us': United States looks to other countries for help with Iran

What else has happened?

Iran’s claim that it had arrested the spies came just days after tensions in the Middle East spiked following the seizure of a British oil tanker by Iran's Revolutionary Guard in the Strait of Hormuz.

The Revolutionary Guard said its naval forces had seized the Stena Impero tanker Friday for allegedly violating maritime rules and regulations in the Persian Gulf. A dramatic audio recording released Sunday provided the tense moments leading up to the raid, which included The Guard's forces rappelling from helicopters to the ship's deck.

British Prime Minister Theresa May, whose three-year reign ends Wednesday, chaired an emergency security session Monday to discuss how to respond to Iran’s seizure of the ship. Britain is considering a number of options to raise the pressure on Iran, but officials say military operations are not being considered.

Other tankers targeted

In June, two other tankers reported they had been attacked about 25 miles off the southern coast of Iran.

The Front Altair, loaded with the flammable hydrocarbon mixture naphtha from the United Arab Emirates, radioed for help as it caught fire. A short time later, the Kokuka Courageous, loaded with methanol from Saudi Arabia and Qatar, also called for help.

The U.S. Navy's Fifth Fleet said it received two distress calls and sent the guided-missile destroyer USS Bainbridge to the scene.

No nation or group claimed responsibility, and Iran denied it was involved in the attack.

Other spy allegations

In recent years, Iran has arrested other foreign nationals it claims have been working as intelligence agents, although they are usually citizens of Iran and a second country. Iran does not recognize dual nationality.

Nazanin Zaghari-Ratcliffe, a British-Iranian imprisoned in Iran at the end of a family visit there in 2016, ended a 15-day hunger strike last month. She was convicted of spying and spreading propaganda, a claim she and her family completely reject.

Iran-American Jason Rezaian spent 544 days in Iran's notorious Evin prison.The former Tehran bureau chief for The Washington Post was convicted of espionage in a trial widely regarded as a sham, but later released amid the nuclear deal orchestrated by Obama.

Iran has also detained foreigners who have no connection to Iran.

Xiyue Wang, an American citizen and a graduate student in history at Princeton University, has spent three years in an Iranian jail, where in January he marked his 38th birthday. Xiyue Wang was convicted of espionage.

In January, Iran’s government arrested a 46-year-old American named Michael R. White, a Navy veteran who reportedly traveled to the country to visit an Iranian girlfriend. White was the first American to be detained in Iran during the Trump presidency.

White’s imprisonment is yet another flashpoint in a longstanding diplomatic standoff between Iran and the U.S. over detainees and hostages that stretches back to Iran's Islamic Revolution in 1979, when 52 American diplomats and citizens were held hostage inside the U.S. Embassy in Tehran.

The longest-held hostage in American history – if he is still alive – is Bob Levinson, a retired FBI agent who vanished 12 years ago this March on the island of Kish, off Iran's southern coast. Exactly what Levinson was doing in Kish remains a matter of dispute.

The Associated Press reported in 2013 that he was on a mission for the CIA to recruit a potential Iranian mole. The FBI still claims he was working as a private investigator, likely probing a cigarette-smuggling ring.

Levinson's wife, Christine Levinson, said she did not know why her husband traveled to Iran. He never spoke to her about the work he did for the government, she told USA TODAY.

A proof-of-life video emerged in 2011. Then, images appeared of Levinson wearing an orange jumpsuit of the kind typically associated with prisons or hostages. Iran says it is not holding him, does not know why he was captured and has no information about his current whereabouts.

Contributing: The Associated Press

A rare look:USA TODAY journalist gets rare glimpse of life in Iran, whose history with US is marked by decades of animosity

Making strides:In Iran, most women must live as second-class citizens, but some are making strides\