When Ethiopia’s intelligence agency recently uncovered a cell of 15 people it said were casing the embassy of the United Arab Emirates, along with a cache of weapons and explosives, it claimed to have foiled a major attack with the potential to sow havoc in the Ethiopian capital, Addis Ababa.But the Ethiopians omitted a key detail about the purported plot: who was behind it.The only clue was the arrest of a 16th person: Accused of being the ringleader, Ahmed Ismail had been picked up in Sweden with the cooperation of friendly “African, Asian and European intelligence services,” the Ethiopians said.Now U.S. and Israeli officials say the operation was the work of Iran, whose intelligence service activated a sleeper cell in Addis Ababa last fall with orders to gather intelligence also on the embassies of the United States and Israel.They say the Ethiopian operation was part of a wider drive to seek soft targets in African countries where Iran might avenge painful, high-profile losses such as the death of Mohsen Fakhrizadeh, Iran’s top nuclear scientist, said to have been killed by Israel in November, and Gen. Qassem Soleimani, the Iranian spymaster killed by the United States in Iraq just over one year ago.Citing Western intelligence sources, Rear Adm. Heidi K. Berg, director of intelligence at the Pentagon’s Africa command, said that Iran was behind the 15 people arrested in Ethiopia and that the “mastermind of this foiled plot,” Ismail, had been arrested in Sweden.“Ethiopia and Sweden collaborated on the disruption to the plot,” Berg said in a statement.Iran denied the accusations. “This is a baseless allegation provoked by the Zionist region,” a spokesperson for the Iranian Embassy in Addis Ababa said. “Ethiopian and Emirati officials did not say anything about Iran being involved in this issue.”The United Arab Emirates angered Iran when it normalized relations with Israel in September as part of a series of agreements brokered by the Trump administration in its final months and known as the Abraham Accords.A spokesperson for the Ethiopian police, which named just two of the 15 people arrested, declined to say why Ethiopia did not finger Iran for the plot. Several diplomats said that Ethiopia, as Africa’s diplomatic capital and home to the headquarters of the African Union, tries to avoid getting publicly embroiled in delicate issues involving major powers.Even so, Ethiopia’s National Intelligence and Security Service said that a second group of plotters had been preparing to hit the Emirati Embassy in Khartoum, Sudan. A Sudanese official confirmed that account.A senior U.S. defense official linked the arrests in Ethiopia to a failed Iranian plan to kill the U.S. ambassador to South Africa, which was reported by Politico in September. The U.S. and Sudanese officials agreed to discuss the matter on condition of anonymity because of its diplomatic and intelligence sensitivity.Still, much about the Ethiopian arrests and alleged Iranian role remained murky. Ethiopian police have yet to formally charge the 15 plot suspects, only two of whom have been identified. Israeli officials say that as few as three of them may be actual Iranian operatives, with the others having been caught in the Ethiopian dragnet.And the arrests in Ethiopia come at a time of heightened political sensitivity in Iran and the United States, as the Biden administration considers its posture toward Tehran and whether to revive the Obama-era nuclear deal with Iran that President Donald Trump scrapped in 2018.Adding to the pressure on President Joe Biden, Iran’s intelligence minister suggested last week that his country might seek to obtain nuclear arms if U.S. sanctions were not lifted soon.While Berg confirmed several details about Iran’s role in the Ethiopian arrests, other military and diplomatic officials in Washington declined to discuss it.In contrast, officials in Israel, whose government is openly hostile to any thaw between Washington and Tehran, highlighted the purported plot as further evidence that Iran cannot be trusted.For all its efforts, Iran has yet to deliver on its promises of vengeance for its high-profile losses, beyond a missile attack on U.S. forces in Iran in January 2020, days after Soleimani was killed.Any plan to hit the UAE, as suggested by the arrests in Ethiopia, would be a curious choice, given its potential to undermine Biden’s putative nuclear diplomacy with Iran, said Aaron David Miller, a foreign policy expert at the Carnegie Endowment for International Peace.Other analysts, though, said that the UAE was high on Iran’s list of enemies and that the embassy in Ethiopia might present an unchallenging target at a time when Ethiopia is distracted by a war that has been raging in its northern Tigray region since November.“Africa is a relatively easy place to operate, and Ethiopia is preoccupied with other issues,” said Bruce Riedel, a former CIA officer now with the Brookings Institution.The murky episode seemed destined to become the latest in a series of cat-and-mouse episodes between Iranian and Israeli operatives on African soil in recent years.During the 1990s, Iran enjoyed close ties with Sudan under autocratic ruler Omar al-Bashir, and in the next decade it was able to dock its warships in Eritrea.