Iranian officials arrested and briefly detained Robert Macaire, the British ambassador to Iran, according to the United Kingdom’s foreign secretary.
Macaire was arrested amid a protest outside of a university in Tehran and detained for more than an hour. He was eventually released, the Iran-based Tasnim News Agency reported.
“The arrest of our Ambassador in Tehran without grounds or explanation is a flagrant violation of international law,” British Foreign Secretary Dominic Raab said in a statement Saturday.
“The Iranian government is at a cross-roads moment,” Raab continued. “It can continue its march towards pariah status with all the political and economic isolation that entails, or take steps to deescalate tensions and engage in a diplomatic path forwards.”
The Tasnim News Agency, which has close ties to Iran’s Revolutionary Guard, claimed that Macaire was arrested on suspicion of “provoking some radical acts among protestors.” The agency said Macaire will be summoned for “further explanations.”
However, reports from the Washington Post and The Guardian say that, before his arrest, Macaire was at a vigil held for the 176 victims of the Ukrainian passenger plane shot down in Iran. The vigil escalated into a protest, at which point Macaire left, the Post reported, citing an official familiar with the incident.
The British envoy was arrested at a sensitive time for Iran and U.S., a close ally of the U.K. Just one day earlier, Iran finally admitted that it shot down the Ukrainian airliner, apparently mistaking it for a cruise missile, after denying responsibility for days.
Iranian officials said that their military was at “the highest level of readiness” at the time of the mistaken target because they feared a retaliation attack for striking two U.S. military bases in Iraq, which were launched after the U.S. killed top Iranian general Qassem Soleimani.
Most of the victims on the plane were Iranian.
Hundreds of people protested at universities in Tehran on Saturday night, angered over the government’s deathly mistake and its initial denial of it, according to the Associated Press.
The U.S. State Department also denounced the arrest and called on the Iranian regime to formally apologize in its own statement Saturday.
“This violates the Vienna Convention, which the regime has a notorious history of violating,” State Department spokeswoman Morgan Ortagus said on Twitter. “We call on the regime to formally apologize to the UK for violating his rights and to respect the rights of all diplomats.”
President Donald Trump ― who ordered the strike against Soleimani, intensifying the strain on the U.S.’s relationship with Iran ― called on the Iranian government to allow human rights groups to remain at the protests over the downed airliner on Friday night.
“There can not be another massacre of peaceful protesters, nor an internet shutdown,” Trump tweeted. “The world is watching.”
The president also tweeted a message in direct support of the Iranian protesters: “I’ve stood with you since the beginning of my Presidency, and my Administration will continue to stand with you. We are following your protests closely, and are inspired by your courage.”