ISTANBUL — Turkey's intelligence agency has detained a Jordanian citizen suspected of spying for the United Arab Emirates, a Turkish official said, in a move that highlights a rivalry between the two governments marked by intrigue and intensifying public acrimony.

The suspect, Ahmed al-Astal, 45, is originally Palestinian and had been working as a journalist. He had confessed to working for the UAE and was expected to appear in court this week, according to the Turkish official, who spoke on the condition of anonymity to discuss intelligence matters. Astal’s work, overseen by Emirati handlers whom he said he knew by nicknames, included reporting on Turkish political developments and keeping tabs on Arab dissidents living in exile, the official said.

Turkey and the UAE have competed for regional influence over most of the past decade, promoting opposing ideological visions that have divided the Middle East. In particular, they have sparred over Turkey’s support for political Islamist movements, which the UAE views as a regional threat. The two governments have also squared off in Libya, providing military support to opposing sides in the civil war.

The arrest marks the third time in the past two years Turkey has detained someone suspected of spying for the UAE. Two men who were arrested in April 2019 were said to be collecting information on Palestinian factions in Turkey, according to local media reports. One of the men, Zaki Hasan, died while in custody, in what the government called an apparent suicide.

News of Astal’s arrest Friday was first reported by the Reuters news agency, which did not reveal his name, and came just days after press accounts suggested Turkey was actively conducting its own aggressive surveillance of perceived enemies abroad. In recent weeks, the Austrian press has reported on the arrest of a Turkish citizen in Vienna who turned himself in to the police and said he worked for Turkish intelligence and had been ordered to shoot a Kurdish Austrian politician. Turkey has denied that the Turkish man ever worked for its intelligence agency.

A media spokesman for the UAE did not reply to a message seeking comment on the allegations against Astal.

Astal lived on Turkey’s Black Sea coast and disappeared in late September, according to his family and colleagues, who feared he had been kidnapped and had launched a public campaign to persuade the Turkish authorities to investigate his disappearance. A brother, Hussam al-Astal, said in an interview that he was not aware of the arrest and did not believe Ahmed, who lived in the UAE until moving to Turkey in 2013, was a spy or had any relationship with the Emirati government.

Rather, he said, Ahmed was considered a dissident by the UAE because of his support for the Islamist Muslim Brotherhood movement. “How can he be accused in this matter?” said his brother, who lives in the Gaza Strip.

A summary of the findings by Turkish intelligence that were shared with The Washington Post suggested Ahmed al-Astal — said to be known to Emirati handlers as Abu Layla — had been coerced into espionage more than a decade ago. He had initially turned down an offer to work for Emirati intelligence in 2008 but relented after failing background security checks when he applied for a job, the summary said.

After moving to Turkey, he “concentrated on Turkey’s relations with the Muslim world, foreign policy initiatives and domestic politics,” the summary said. He was also tasked with establishing whether the government of President Recep Tayyip Erdogan, which survived a coup attempt in 2016, was vulnerable to another one. And he “passed information to the UAE about Turkey-based Arab journalists and dissidents, who may be vulnerable to recruitment efforts by Emirati intelligence,” the summary said, including recordings of meetings with Brotherhood-linked dissidents.

On at least one occasion, in the spring of 2016, an Emirati intelligence official visited Astal in Turkey, but otherwise he communicated with his superiors remotely, using chat programs as well as custom messaging software his handlers had installed on Astal’s computer, according to the summary. After initially threatening his livelihood, Astal’s handlers paid him approximately $400,000 over the period he was in their employ, it said.

The summary did not say how Astal came to the attention of Turkish intelligence. The Turkish official said Astal was on the run for a few weeks before he was captured.

The threat Arab dissidents face in Turkey came into sharp relief after the killing of Jamal Khashoggi, a Saudi journalist critical of his country’s government, in Istanbul by Saudi agents in 2018. But even as Turkey has sought to highlight domestic interference by its overseas adversaries, its own pursuit of enemies abroad has come under growing scrutiny.

The latest episode, in Austria, unfolded after a 53-year-old Turkish national named Feyyaz Ozturk turned himself in at a police station in Vienna in September. He said he was a Turkish intelligence agent with orders to shoot Aygul Berivan Aslan, a former Kurdish politician who was critical of the Turkish government, according to a police report.

Ozturk’s confession was first reported by Zack Zack, an online news outlet, and the New York Times.

Turkey’s ambassador to Austria, Ozan Ceyhun, told Turkey’s state-run Anadolu news agency that Ozturk “does not have any relationship with Turkish intelligence and my country.”

Hazem Balousha in Gaza and Loveday Morris in Berlin contributed to this report.