The small boats, used largely on coastal waters and on rivers, had been en route from Kuwait to Bahrain in the Persian Gulf when they disappeared from the Navy’s scopes. Senior administration officials said the vessels appeared to have experienced mechanical trouble or ran out of fuel, but Fars, an Iranian news agency, said the sailors had been “snooping.”
The Iranian military took the boats and their crews to Farsi Island, where Iran maintains a naval base in the northern Persian Gulf.
The run-in, which drew calls for reprisal from Republican lawmakers and candidates, comes at a sensitive time in the tumultuous relationship between the United States and Iran. Economic sanctions against Iran could be lifted as soon as this month under a landmark deal aimed at preventing the Islamic republic from building a nuclear weapon.
A senior defense official said of Tuesday’s incident that there was no indication of hostile intent and that the American crews were being well-treated. “In some ways this has been very professional,” the official said.
“We have received assurances from the Iranians that our sailors are safe and that they will be allowed to continue their journey promptly,” said White House press secretary Josh Earnest on CNN.
A senior administration official said that, after communications between Secretary of State John F. Kerry and Iranian Foreign Minister Mohammad Javad Zarif, the State Department believed the situation had been resolved.
Kerry “made the case very strongly” to Zarif that the incident had stemmed from a mechanical problem aboard one of the boats and that they appeared to have drifted into Iranian territorial waters. Small U.S. naval craft frequently patrol the Persian Gulf just beyond Iran’s territorial limit.
Zarif asked for more information about the incident, which the State Department later communicated to Iran. Zarif, the official said, “came back and said they were all safe and sound, that nobody was hurt,” and that Iran would “return them promptly.”
“We’re expecting them sometime around sunup” Iranian time, the official said.
A U.S. defense official said he expected U.S. personnel would be “taken out to international waters by the Iranian Coast Guard and turned over to a U.S. ship,” the official said.
Another official, noting Iranian media reports that the sailors had been “arrested,” acknowledged that there is more than one power center in Iran but expressed cautious optimism that the sailors would quickly be released.
The incident marks the latest run-in between Iranian and U.S. crews. In December, Iranian gunboats fired unguided missiles about 1,000 yards from the aircraft carrier USS Harry S. Truman.
A U.S. defense official said the small boats were believed to have been within 12 nautical miles of Iran when they broke down. Many officials stressed, though, that it is unclear exactly what happened.
The vessels, known as riverine command boats, are agile and often carry Special Operations forces into smaller bodies of water.
The U.S. government has been in communication with Iranian authorities, according to a senior defense official who spoke on the condition of anonymity to discuss sensitive intelligence issues.
“We have received assurances the sailors will promptly be allowed to continue their journey,” the official said.
Defense Secretary Ashton B. Carter was updated throughout the afternoon about the incident and spoke with Secretary of State John F. Kerry and national security adviser Susan E. Rice.
In recent weeks, U.S. lawmakers have called for increased sanctions on Iran after the country tested two ballistic missiles in recent months. Since the tests, President Hassan Rouhani vowed to expand the country’s ballistic missile program.
Many U.S. politicians also complain of Iran’s support for allied militant groups across the region and for President Bashar al-Assad in Syria.
Even though details about the incident were sparse, former Florida governor Jeb Bush, a Republican presidential candidate, quickly weighed in.
Sen. Tom Cotton (R-Ark.), who opposed the nuclear deal, said on CNN that “this kind of openly hostile action is not surprising. It’s exactly what I and so many others predicted when President Obama was negotiating the nuclear deal with Iran—that it would embolden their aggression towards the United States and our allies in the region.”
Carol Morello and Karen DeYoung contributed reporting