Britain took new steps on Monday to distance itself from the Trump administration’s escalating confrontation with Iran, even while pushing for the release of an oil tanker seized by Tehran three days earlier.
British efforts to bolster maritime security in the Persian Gulf “will not be part of the U.S. maximum pressure policy on Iran,” Foreign Minister Jeremy Hunt said after an emergency cabinet meeting about the tanker.
Mr. Hunt’s pointed statement was the first indication that a broad disagreement over Iran still persists between the two allies despite the Iranian seizure of the British-flagged tanker on Friday.
On the American side of the divide, Secretary of State Mike Pompeo insisted on Monday that both the British and American disputes with Iran arose from the same essential cause: the fundamental character of the Iranian government.
“This is a bad regime,” Mr. Pompeo said in an interview with Fox News.
Iranian officials have said the Islamic Revolutionary Guards Corps seized the tanker, the Stena Impero, for various infractions like polluting, but also as retaliation for the British impounding of an Iranian tanker off the coast of Gibraltar two weeks ago. Britain said it had detained the ship on suspicion of violating a European Union embargo on the delivery of oil to Syria.
Many analysts and some former British diplomats had wondered if the tanker “tit for tat,” as Mr. Hunt called it, would push Britain into closer collaboration with the Trump administration in its own showdown with Iran.
Last year, President Trump withdrew from a 2015 accord that the United States, Britain and other international powers had reached with Iran to trade relief from economic sanctions for limits on its nuclear program. In May, the administration hit Iran with sweeping new sanctions in an attempt to force it to negotiate a new and more restrictive agreement.
Iran has called the new sanctions “economic warfare,” and since May it has begun calibrated steps to restart its nuclear program, exceeding limits on uranium enrichment imposed by the 2015 deal.
At the same time, Iran has taken steps like the seizure of the tanker that have reminded the international powers of the country’s ability to threaten the flow of shipping out of the Persian Gulf through the narrow Strait of Hormuz. The channel accounts for a fifth of the world’s oil supply, a quarter of the liquefied natural gas, and a half a trillion a dollars in trade every year.
Britain has so far joined France, Germany and the European Union in trying preserve the 2015 deal in defiance of Mr. Trump. Any hope of success would almost certainly be doomed if Britain were to react to the seizure by joining the United States in re-imposing sanctions.
But Mr. Hunt, the foreign secretary, instead reaffirmed the depth of the government’s disagreement with the Trump administration despite Britain’s own rising tensions with Iran over the tankers. “We remain committed to preserving the Iran nuclear agreement,” he said.
In the government’s most substantial response yet to the seizure, Mr. Hunt said that Britain was now dispatching additional warships to the Persian Gulf while working in concert with European allies to better guard commercial traffic.
“If Iran continues on this dangerous path, they must accept the price will be a larger Western military presence in the waters along their coastline,” Mr. Hunt warned. He described the new maritime security effort as “European-led.”
Although the United States has said it intends to lead its own multilateral maritime security operation in the Gulf, Mr. Hunt said only that he would talk to Washington “later this week” about how “to complement this with recent U.S. proposals.”
Britain is now deploying its Navy “with a heavy heart,” Mr. Hunt said, “because the focus of our diplomacy has been on de-escalating tensions, in the hope that such changes would not be necessary.”
Iran, for its part, released photographs indicating that the 23 crew members of the seized tanker were in good health.
But the broader overtones of the conflict with Washington continued as Iran also announced that it had arrested 17 Iranian citizens on charges of spying for the United States.
The Iranian announcement, which did not include the names of those arrested or offer any evidence of spying, drew a swift denial from the White House.
“Zero Truth. Just more lies and propaganda,” Mr. Trump wrote on Twitter, calling Iran “a Religious Regime that is Badly Failing and has no idea what to do.”
Mr. Pompeo, in his interview with Fox News, was equally dismissive. “The Iranian regime has a long history of lying,” he said, casting blame on its supreme leader, Ayatollah Ali Khamenei.
“It is part of the nature of the ayatollah to lie to the world,” Mr. Pompeo said.
Sidestepping the chronology of American actions and Iranian responses, Mr. Pompeo asserted that what Iran is doing “isn’t because of the American sanctions.”
“This is because the theocracy, the leadership in Iran, their revolutionary zeal to conduct terror around the world for now four decades continues,” he said.
In contrast to more conciliatory statements occasionally made by Mr. Trump himself, Mr. Pompeo appeared to leave little room for negotiations with the current Iranian leadership. “I am ultimately convinced,” he said, “that the Iranian people will get the leadership behavior that they so richly deserve.”
Mr. Pompeo also disclaimed any American responsibility for the captured British tanker. “The responsibility in the first instance falls to the United Kingdom to take care of their ships,” he said.
In a new conference to announce the arrest of the 17 unnamed spies, an Iranian counterterrorism official said they had been recruited and trained by the C.I.A.
A running battle to root out American spies is a staple of the news media in Iran, and its English-language Press TV recently broadcast a documentary about what it called a successful “mole hunt” for C.I.A. agents.
The Iranian intelligence minister, Mahmoud Alavi, claimed in the documentary that the spy hunt had resulted in the C.I.A. “crumbling like a house of cards,” according to a report by the BBC monitoring service.
Iranian television this year also broadcast a fictional series, titled “Gando,” about the exploits of heroic counterintelligence agents battling a villainous American spy who is undercover as a journalist.
The director and producer have said that the villain is modeled on Jason Rezaian, a reporter for the Washington Post who spent 18 months in an Iranian prison on charges of espionage, which he and American officials denied.
Mr. Rezaian, in a Twitter post last month, said the resemblance was only superficial. “Besides being fat, bald and wearing glasses,” he wrote, “there is no similarity to me or anything that has happened in my life.”