Washington: U.S. Secretary of State John Kerry thanked Iranian authorities on Wednesday for their cooperation in the release of 10 American sailors who were taken into custody in the Gulf and credited diplomacy with resolving the situation.

‘I think we can all imagine how a similar situation might have played out three or four years ago, and fact that today this kind of issue can be resolved peacefully and efficiently is a testament to the critical role diplomacy plays in keeping our country safe, secure, and strong,’ Kerry said in a speech at the National Defense University.

Four photographs published by Shargh Daily, a Tehran newspaper, and posted on Twitter, purportedly show the moments after one of the U.S. boats was stopped by the IRGC.

Iranian state television released footage of the arrest, showing the sailors as they knelt down with hands behind their heads and their two vessels being surrounded by several IRGC fast boats.

The video showed weapons and ammunition confiscated from the sailors, who were seen eating food provided by the Iranians. There were also images of American passports being inspected.

The incident raised tensions between Iran and the United States, which, along with other world powers, reached the deal under which Iran will curb its nuclear activities in exchange for the lifting of economic sanctions.

Some conservatives in both countries, enemies since Iran’s 1979 Islamic revolution, have criticised the deal that is due to be implemented in the coming days.

Iran freed 10 U.S. sailors on Wednesday, a day after detaining them aboard two U.S. Navy patrol boats in the Gulf, bringing a swift end to an incident that had rattled nerves just before the expected implementation of a landmark nuclear accord.

Iran’s Islamic Revolutionary Guard Corps (IRGC) said it had released the sailors after determining they had entered Iranian territorial waters by mistake. IRGC Rear Admiral Ali Fadavi said the boats had strayed because of a broken navigation system.

There were no indications the sailors were harmed while in Iranian custody, the Pentagon said. The quick resolution contrasted with previous cases in which British servicemen were held considerably longer, in one case nearly two weeks.

Iran expects the U.N. nuclear watchdog to confirm on Friday it has curtailed its nuclear programme, paving the way for the unfreezing of billions of dollars of Iranian assets and an end to bans that have crippled oil exports.

In a statement carried by state television, the IRGC said the sailors were released in international waters after they apologised.

Iranian state television later released footage of one of the detained men, identified as a U.S. Navy commander, apologising for the incident.

‘It was a mistake, that was our fault, and we apologise for our mistake,’ the sailor said on IRIB state TV.

A Pentagon spokesman, Commander Gary Ross, said the video appeared to be authentic, ‘but we cannot speak to the conditions of the situation or what the crew was experiencing at the time.’

A U.S. defence official, speaking on condition of anonymity, said: ‘Clearly this staged video exhibits a sailor making an apology in an unknown context as an effort to defuse a tense situation and protect his crew.’

U.S. Vice President Joe Biden earlier rejected reports that Washington itself had offered Iran an apology over the incident.